Thank you for your feedback!

Blocking a channel can be done even easier:
All you have to do is to press the 'x'-Button which is placed next to the channel name.

To be even more precise, the instructions you gave do not work with our Add-on. Channels are blocked by their name, not by their id. Therefore, it is necessary to input the channel/user name, not the id of the channel/user (assuming you are blocking manually).

If you disagree with us, please contact us under yt-cleaner(at)protonmail(dot)com, so we can solve this mystery.