OpenLiteSpeed reverse proxy fail - need help

Hello everyone! Few days ago i have installed OpenLiteSpeed on my Ubuntu server 18.04 LTS. I have used nginx before, im hosting mostly Wordpress sites, and i seen a few tests about OLS great performance.
I have successfully set up my server, the WP sites runs well (the TTFB is a bit with OLS higher than nginx). Im hosting a Ghost CMS based blog - its working abnormally slow, sometimes runs to 503 error - but this isnt the biggest problem.

I cant find a working reverse proxy tutorial for OLS. I want only basic reverse proxy like: run some web based apps on subdomains.

example: - reverse proxy to (this is my srv, that runs OLS, Webmin, some other stuff)
or another: - reverse proxy to

Can somebody help my how can i do this with OpenLiteSpeed?