Hey!
I am trying to create a side scroller game for mobile and I don’t know how to create a BP class that will generate every time new random map and place enemies or traps in random on the map.
Any ideas?
Thanks! 
Well that’s a quite large question you ask there.
There are multiple different approaches beginning from modular pieces of a level which you design and then just put one after another up to a completely generated terrain.
Remember: The more you generate rather than designing and then use it the harder it is to make a decent generation with good gameplay.
For a very easy example on how to do random generation you can check out “Tappy Chicken” from the marketplace (it’s a free demo project). It’s doing exactly that for a flappy bird clone (placing the pillars in different heights to create an endless level).
There are a few tutorials on youtube about how to do very basic procedural generation. For example this one:
https://youtube.com/watch?v=6RqDo3012YA
I hope this helps you a bit. Without a more specific question this is about all I can do.
Cheers
look at my 2d infinite runner it can help you
Thank to both of you, it’s exactly what I’m looking for.