Well your not gonna do much if you not familiar with how to use the UE4 cause I understand Unity is much different from this.
1 http://www.creativebloq.com/3d/25-tips-unreal-engine-4-71621196
2 Just start learning how to use the UE4 cause it may not be your thing. Many come and go mainly go.
Best place I know is this.
https://youtube.com/watch?v=QMsFxzYzFJ8
Many just single out areas and make assets, music, ect
watch the whole thing a couple times then see wat strikes. or just get in. To theorize in contemplation is ti just make excuses trust me I am a master.
It sux relearning and relearning but that is what we do we relearn where we figed up. Mistake makes headstrong. Start by making asset. like rocks etc.
Trust me over time if u make yourself a planner in assets you will kiked 2 or 3 birds at one time. One u have original assets you can redo these asset will be your trophies. Yea they look familiar in beginning over time they will open up.
You will do like most of us do. We come here asking questions and not the leg work to see. I am guilty. Trust me. I dnt want to do this at times. But their are time I blow my own mind.
( I am a Legend in my own MIND). Many suffer from this until we face the fear of “what is I mess up”. Dude that is the key to learning. Make mistakes,redo. In guitar training you repeat scales till ur fingers bleed. My suggestion is to go to cgtextures.com dl them get gimp with Insanebumbs and you have the best. The freebies are as good as the 3k ones. trust me