How do i make it work on the web?
Does this mean I have to use a code like most others have example instead of donate , this would be" paypal or subscribe"
How do I change this and in cooperate the above to work together.
I'm afraid I don't really understand what you're asking. The user upgrades system is a specific system where people pay to have extra groups/permissions applied to them. If you want something else (such as donations), the system is likely not appropriate for that.
Previous one with the donation is only an example.
I want exactly as you mentioned how do i make it work.
I have group A for premium use.
How can I make it work so that this group pays automatically for this service.
Recently I am spending more time to improve the website and able to understand more
This is what user/account upgrades do, so I'm not sure what your question is at this point. You setup the user upgrade in the control panel as you want it and enter your PayPal account information, then people can purchase it from within their account.