How to create new rails app in Rails droplet and run it

I recently set up a Ruby on Rails Droplet and I added Bootstrap to it so it would look nice. Then I was trying to add esbuild as the javascript bundler. I don’t know what the default one is. I kept getting errors whenever I tried to install it. I would comment out one thing and other errors would appear. I decided to just create a new Rails project with esbuild and bootstrap added by default. Normally I use “rails server” to run it but the droplet uses systemctl or whatever to make it so the server is always running in the background and I can do other things while it’s running (which is pretty cool). If someone could help me figure out how to install/add esbuild or set up the systemctl thing so I can run my new project that would be very helpful. I don’t know if I can edit this after I submit it or if I should include the errors that I’m getting now.

I would like to have it where the server is running in the background so I can do other things as well. How would I configure systemctl to do that?