Issues with setting up the Upgrades Plugin


I am new to the site. Bought a membership just for the Upgrades plugin. Basically, I want to allow users to use the Domain Mapping plugin and to upgrade their storage space on the website.

I've seen a few posts about this but I still don't quite understand exactly what I am doing. I am not a PHP master so I am looking for a little extra help in walking me through the steps. I followed the installation process for the Upgrades plugin. All the files are in the correct place. I copied the "quota" plugin to wp-content/mu-plugins/upgrade-plugins/ but whenever I try to create a new package, it doesn't appear under any of the 15 plugin dropdowns. Also, how do I setup the Domain Mapping plugin to work with upgrades? I want users to pay for me to setup domains for them through my own licensing and parking service. I understand the process of parking the domains, but how do I get it integrated with the Upgrades plugin? I know I have to add the code to the plugin itself, but will it still appear in my Site Admin menu if I put it under mu-plugins/upgrade-plugins?

Also, is there a way to remove the options for 1 month and 3 month from some packages? I would like users to pay for the space quota upgrade yearly only.

Thanks to anyone who can provide me with detailed instructions.