@skywatch Hm, I'll try splitting it once again:
Preliminary requirement, when you have your domain and nginx, follow a tutorial to set up LetsEncrypt with nginx, there are plethora of guides way better than what I can explain
If you have your configuration (probably in /etc/nginx/sites-available/default) then you find the server { section that has your TLS (SSL) configured in step 1, then you just paste in the described content
Find the folder where you installed mycontroller, the folder has a www folder in, find [mycontroller_install_directory] with that path (e.g. /home/mycontroller/www)
The same www folder, run the find ... commands in the folder, it automatically precompresses the folders's contents
Make a new configuration file in /etc/nginx (e.g. mycontroller_http2_push.conf) and place the lines that start with http2_push in the file. Make sure the filename in the location / block matches with the configuration file name you made.
Restart nginx and it should now display you mycontroller with encrypted connection and really rather fast.