Collectible Card Game Headquarters

I've tried to chose 2 commaders to try out the new Partner mechanic and I'm not able. Maybe there is an easy way but I can't seem to find?
Is it implemented or am I that clumsy?

Thanks in advance guys.

yeah the GUI is a bit difficult, you need to MultiSelect them with CTRL or SHIFT and then you can add all of them at once.

Otherwise they will replace each other.

Thanks a lot!

And in the mobile version Do you know how it is done?

I also need to know how to use partner commanders on a galaxy s6