You can find repositories pretty easily with a google search if I remember correctly. Let me see real quick....... Yep two sources came up with a search of recloudstream repository . One from github and one from rentry. Look for cloudstream 3 or recloudstream.
Its really simple open cloudstream and go to their website page where u downloaded their app. From there click repositories, then click install to the repositories you want to download. It will redirect to the app and ask u if you want to download all providers. You could also do it manually and add the url to the app by copying the url. It is very simple and convinient.