.env

[xerieox]

I am trying to set it up with the source code and cannot find the .env.

[AkimotoRyou]

Where are you trying to install this?
ReplIt? Linux VPS? Windows?
ReplIt have different menu to edit .env file, they should have FAQ answering this question.
Linux hide any file that starts with dot(.) by default. Just click ctrl+h to toggle this feature.
When asking question, always provide necessary details and do your research beforehand, most of the time someone else already asked your question and got the answer.