Installing Python package with "invalid channel" message

I am trying to install a Python package (ttkbootstrap) using Anaconda (to keep my environment consistent), but it’s not available through the default channel, and when I try to add a channel by giving the URL I have for the package, I get an “invalid channel” message. Perhaps I am misunderstanding the process. Can someone point me to the appropriate documentation, or do you have a solution? Thanks!

I what to install it in my destop so that i can learn to code very well