Intallation 500 Internal Server Error

I'm having trouble with an initial installation of Akaunting on my server. Everything I've tried - automatic and manual installation attempts - have left a "500 Internal Server Error." I've checked and confirmed my host meets all the requirements. I've attempted letting Akaunting try to do a self install, and I've attempted revising the ".env.example" file. I'm not a programmer/developer, so in trying to follow the instructions (https://akaunting.com/hc/docs/on-premise/installation/) I used various data, because the screenshot for the ".env" file is somewhat ambiguous to me.

I also saw that if there's not a previous version of Akaunting installed, then doing this manually pretty much won't work. (Unless that note is related to updates.)

Anyone have any suggestions?