Honestly, Google is your best answer. Do a quick Google search on how to add Real Debrid to Kodi as you have to change URL resolver settings etc and then do a search on how to add it to Covenant. It's dead simple to do. I would detail it all in here, but there is so much text it would take up loads of pages.
Here is the link to signup, you need the Real Debrid Premium service, payment is in Euros
https://real-debrid.com/premium
Terrarium, there is an option in settings that says 'Real Debrid' you just tap onto there and add your details in.
As I say, I haven't used RD for quite a while, so I can't comment on the quality of the links lately, but there were all spot on when I last used them, about 3-4 months ago.
They do a 30 day account which is 4 euros, you can then do longer for a higher cost, so it makes sense to just sign up for a cheap one to start with and see what you think.
Kodi RD setup......
https://seo-michael.co.uk/how-to-configure-real-debrid-in-kodi/
Covenant RD setup..........
Terrarium......How to install Terrarium, plus it also covers adding RD account.........