Adding coins to multiple collections?

Hello,

I promise I tried really hard to figure this out on my own before asking :-)

I have created new "sub" collections in my user settings, in addition to "default" collection.
I can not find the option now to add a coin to these new collections. Is it in "my coins"? Or under "catalog" when I add a new coin entirely? I just don't see it anywhere.

Please let me know if I am missing something with this great new feature or if I indeed have a bug. :-)

For example, this image from the NumisDoc tutorial:


But this image is what I see: (button is missing)

That's because you are using the old format, you have to switch to the new one.
Your account --> Settings --> Personal Options at the bottom
Display of my collection
tick : One line per coin in my collection, with coin values

Wow, I didn't even know there was a "new" format.
Thank you very much for pointing that out to me :-)