Channels added to your account via the website will be added the next time your Roku auto-updates. You can cause it to update manually via Settings > System > System update.
Note that some channels rely on the enhanced capabilities of newer Roku models and may not install on older discontinued models that are no longer receiving software updates from Roku.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X