Hey there!
Through your gameserver, you should be able to install any framework you wish, through the use of FTP client such as Filezilla in order to transfer the files, as seen in our guide here. Likewise, you would have to use the database that is provided on your ZAP-Hosting panel and import DB files into there.
From looking at the RedEM:RP docs for example, the installation requires you to install a few resources, as well as a database. This can be done once again through FTP for your resources. You can gather your database connection string from the ZAP panel and also access your database through a link that is provided, in order to create the tables and import the .sql file that the framework would require.
I recommend having a quick glance over our RedM resource installation guide which shows how you can download and install the necessary resources that the framework docs describe to your RedM server. For reference, you can edit your server.cfg on the ZAP-Hosting web interface panel.
Hope this helps! 
~ J