Where are game apps' storage files saved? I would like to delete them I installed The Trail on my Moto E 4. 
I uninstalled it. But, I thought I might try the game again. So, I reinstalled it. But, the game started up from where I left off the first time.
So, how do I get rid of the previous game data files?
It seemed like the second installation took a lot less time.

I am new to these larger games. I have tried a few of the smaller ones like Float Plane. (Are files for that game still on my phone, too?)

I do have a File Manager app.
You can go to Settings > Apps > The Trail > Storage then click Clear Data and Clear Cache 

If The Trail requires you to log into an account or Google Play Games than either delete the account data, or create a new account.