I don't know what spec PC you have but, I assume you have something decent so I would get Elite Dangerous: Horizons, so you can do planet based stuff. So you might as well get the Deluxe Commanders pack so you have it all.
For starting out, there are some tutorials in game that are worth working through so you understand the mechanics of navigation, docking and so forth.
There are a shit tonne of controls to learn and configure, to suit your set-up. Elite Dangerous is fine as a mouse and keyboard game (I know people who exclusively play it that way) but, for me it is a game that benefits from a HOTAS. The Thrustmaster T-Flight X is a great entry level HOTAS that doesn't cost the earth. Above that there is the X52 (which I recommend and you can sometimes hunt down on e-bay cheap) and then there is the X52-pro which the games controls are modelled on (the actual joystick in the ships cockpit is the X52pro) but, I would only recommend the X52pro if you can find it cheaply as it offers little in the way of benefits over the X52. Whatever control mechanism you use (some folk use the XBox controller on their PC for ED), its worth taking time to get the feel for it.
After that, it really depends on what you want to do. Missions early on are a nice way of making money to afford your first ship upgrades or to buy a new ship. It is easier to make money now than it was at launch, with more variety to how it is earned. So you won't be staying in the starter ship for long and the credits to buy and fit a bigger ship come soon enough.
Missions can be very lucrative but, you the best paying ones come with having a high reputation for a given minor faction and having high rankings in Combat, Trading and Exploration. The Ancient Ruins mission, which takes a long time to complete (and I've no idea how to access it), is worth about 100million.
I wouldn't get stuck into combat until you either have upgraded your starter Sidewinder or have amassed the cash to buy something with a bit more combat grunt like the Viper MK III. Outside of combat missions, the places to look for pirates are at system Nav points or in Resource Extraction Sites (RES), found in the rings of gas giants in certain systems. RES come in four tiers of difficulty Low RES, RES, High RES and HAZ RES. Never fire on a ship until you've finished scanning it to confirm it is "WANTED." To earn extra cash from bounties, fit a Kill Warrant Scanner.
All ships come with a basic discovery scanner as standard, so it is possible to get stuck into rudimentary exploration straight away although you won't earn big money from this without all the requisite gear, which requires a slightly larger ship and few million for the required ship modules. Still, the new commander guide has helpful exploration info in it.
https://imgur.com/a/i7KFVThe "Roads to Riches Pathfinder" is a helfpul index of planets with high value targets such as Earth Like Worlds (ELWs) all found around "the bubble" so, you don't need a super long jump range ship to do this exploration (although it does help. I wouldn't recommend doing exploring with anything less than a 20LY range and a decent fuel scoop). Visiting all the systems in this guide will earn you about 250million credits all told, once you turn the exploration data in. Keep in mind that if you crash or otherwise get destroyed, you lose any exploration data you've not submitted.
https://www.alpha-orbital.com/pathfinderTrading is trading (also covered in the new starter guide) and is a reliable way to make cash. In the guide you will find a rares trading route, which is a good way for to make money trading in a smaller ship, as the rares are finite in number and most trading can be done with 20tonnes of space. If the life of a long distance space trucker is for you, then trading is the way to go.
Mining is also covered. I ain't mined jack, so can't advise. But, its covered in the new commanders guide.
The ten powerplay factions are a way to make a steady income as well. Signing up with one of those factions and getting your standing with them to level 3 or 4 (and keeping in there) will earn a steady 5million a week. Which isn't bad but, honestly, there are more lucractive ways to make money out there. The main reason to join a Powerplay faction is for the rank specific items you can access and also, if you enjoy this sort of thing, actively participating in a massive effort to extend the political influence of your chosen faction in the galaxy.
The games two biggest overall factions are the Federation and the Empire. They have their own individual faction reputations and ranks. Higher ranks give access to certain ships and the very highest ranks allow access to two of the biggest, and most potent, ships in the game.
MOST IMPORTANT BIT OF ADVICEDo not fly what you cannot afford to lose. If you do not have the credits to cover the rebuy cost of your ship (typically 5% value of the ship plus fittings), then you will find yourself back in the sidewinder if you get destroyed. Always make sure you have a healthy reserve of credits.
Also, keep in mind that new ships are sold as stock. So they have the lowest rated modules for their core and optional fittings. Some ships fly like ass until you get decent thrusters inside them. As a rule, never buy any ship unless you can afford to buy D rated modules (at minimum) for all the core internal modules. The titular Cobra MKIII only costs 349k credits to buy but, to give it a full A-rated fitting, you're looking at spending over 7million credits. Buy comparison, the stock sidewinder only costs 700k to A rate. The cost is all the module size, with size 1 and 2 modules costing very little and then the prices escalating quickly above size 3 modules. A Python will set you back 56million to buy the stock ship. A class 7A powerplant for a Python costs 51million!
In summary if you have 6million credits, buy a Cobra MKIII, splurge your remaining millions on fitting it, leaving you few credits left and then suffer a tragic accident at the hands of a pirate/asteroid/station wall, you will be a very sad panda.
Do not fly what you cannot afford to lose.
