Before making a game

it is kind of a stupid question but what should i learn and do Before making a game in UE4?

Depends on what you already know, what kind of game you plan to make,
and how much time can you afford to spend.
You can make simple games and apps using just textures and blueprints(visual scripting),
or you can dive deep, have detailed 3D characters and environments and could learn to do it with C++.
Another very important part is the purpose of your game, you should think about this well,
what platforms you want to target, do you want to make it free?, or do you want to make money with your game? maybe both? in that case you’d also need a marketing strategy plan before you even start working.
Marketing is just as important as having a product to sell, unless you happen to create some really cool game that goes viral. My advice would also be try to find someone else or even form a team , in the long run it’s much better than working alone.

https://docs.unrealengine.com/latest/INT/GettingStarted/index.html?utm_source=uelauncher&utm_medium=software&utm_campaign=learntab

Marketing strategy?
all i want is to make paid and free games in iOS and Android, and after that i will move on to PC

Yes well the point is that you probably want and need to make some money with the games you will make to be able to keep working, and selling games is no different than selling any other product, meaning marketing has just as important role in the process as having a game to sell, I speak from experience, if nobody knows your game exists how will they find it? Especially these days, last time I heard, the AppStore had like 1 250 000 apps, woot, what a mess. So that’s why I said that, a few months ago I was invited to some App Developers Strategy Workshop and we talked mostly about monetizing apps and how important it is to make a plan before you even start creating a game. What section of population will your game target? How to implement hidden logs to research which buttons people press most times when they play your game and things like that, details like that can really help improving your game. So that’s why I also said it’s a good idea to form a team, cause lets face it , just the marketing part could be a full time job for 1 person, so others can focus on game Development. I’m not trying to confuse you with this, I encourage you to go ahead and start creating your game, just keep this in mind as well. Good Luck :wink: