With Netflix and Amazon it’s the same deal. If you have a Netflix account (with streaming) or Amazon account (don’t *have* to have Amazon Prime, but you get a lot of free content if you do), you add the channels, Roku displays a code and gives you a web site to go to, you go to your computer and access the web site, log into your Netflix/Amazon account and enter the code.
And you only need to put in codes for Pay stations.
Things like Dailymotion or FoxBusiness are added from the “Channel Store” straight to the Roku.