How do I host wefwef on my own instance?

I’m hosting my own private instance for lemmy and would like to do the same with WefWef.

Here‘s what I want to achieve:

Selfhost WW on app.syrma.cc

I‘m using a Hetzner VPS and would like to install WefWef on the same machineurrently running lemmy (installed with ansible). I know how to create the A record but I‘m not sure how to install WefWef using the guide on github without torpedoing my lemmy installation.

Restrict access so that only my own instance can be used with it

Unfortunately I don‘t have the bandwidth to share the app with others. Is it possible to restrict the app like that by changing some configs?

Issue a SSL cert for the sub domain

I guess running letsencrypt and adding the cert to my nginx config should do the trick.

Would someone be so kind to give me a step-by-step guide on how to do this? I don‘t have a lot of experience with selfhosting and appreciate any help.