Hi there! Let me elaborate what i faced. First i am newbie for linux environment.
Both Linux and Nextcloud are lattest Versions
(Note: Docker is not used here)
I installed Ubuntu Server on one VPS provider, then i created cPanel subdomain under my main website like this
on live production VPS
cloud.mywebsite.com , then i made it point to my VPS IP from zone editor section, then i watched one tutorial on YouTube teaching on how to install Nextcloud with this scenario
Ubuntu Server > Apache2 >PhP 8.1 > MariaDB > Nextcloud > LetsencryptSSL
I follow along the tutorial and everything worked well. I was happy 
.
After some moment my happiness is gone 
Iinstalled OnlyOffice from Nextcloud app center then i tried to activate which requires Secret key and Document Server address, i tried some methods from internet suggestions but most of them are talking about docker, ngnix which is not related to my issue. Kindly help me resolve this with step by step solution without messing up the current used method.
Thanks 
Hello @contact
Please note that you also need to install ONLYOFFICE Docs (Document Server) to connect it to your Nextcloud (please see all available installation options here). Basically, connector app that you’ve installed via Nextcloud interface is used to establish connection between Nextcloud and Document Server.
Once Document Server is installed, you can proceed to configuring connector app to connect it to your Nextcloud. Please see Configuring the ONLYOFFICE connector for Nextcloud block here:
If you haven’t installed Document Server yet, and you are planning to install it on the same server where Nextcloud has already been installed, please make sure to properly configure ports as the necessary ports may be occupied by other applications. List of required ports you can find here:
Thank you for taking time and responding to my question by understanding my issue, Would you kindly guide me by steps of what to write on Ubuntu server … if you don’t mind .
First of all, please see system requirements for ONLYOFFICE Docs:
For Ubuntu you can either install it via DEB/RPM packages or via Docker:
Make sure to use open ports for installation if you are planning to install Document Server to the server with other applications.
Sorry to say this, the learning curve is to much, i followed the steps it didn’t worked, some articles says, i have to switch to ngnix server, but i am using apache2. Some says use docker, i don’t know that docker may create problems or ruin my current working nextcloud. ahh really i am confused , there is no how to tutorial with clear path, doing it on live server not local machine.
Well, you may try installing Document Server via script:
https://helpcenter.onlyoffice.com/installation/docs-community-install-script.aspx
If your Nextcloud is running on default 80 port, make sure to use another one for Document Server, -dp in the guide will help you with that.
By the way, you can also get a subscription for ONLYOFFICE Docs Cloud which is the solution that is hosted for you. You can start a trial to see how it works:
After completing a registration you will receive an email with address, JWT secret and JWT header that you will have to use in the connector app settings to connect Document Server to your Nextcloud.