So, I would like an explanation of how I “build” a game on unreal engine 4, how I put the menu, phase 1, phase 2, phase 3 epilogue and credits.
Do a search for a tutorial, that’s way too general of a question for someone to answer for you and there’s plenty of step by step guides on doing specific things and complete projects to look at
There’s tons of both official and unofficial resources in form of video tutorials, articles, documentation, content examples, free content packs. It’s impossible to not stumble upon it even if you don’t want to. If you want others to help you, you need to first show that you’ve invested at least some essential effort yourself.
Just go to https://www.unrealengine.com/ , click Learning & Support button at the top bar and be overwhelmed by the amount of learning resources you are provided for free. Same applies to YouTube, by just merely searching UE4 followed by whatever you are interested, for example “UE4 Menu”.