on chess . com, how do you play chess 960

Yes, it's not your fault. A lot of the icons don't make sense until you have them explained.
When you go to live chess or daily chess, you see a 4x4 chess board icon. This is supposed to represent standard chess. You'll notice a drop-down arrow. If you click it, a list of variants, including chess960 will appear.
Is this possible on mobile? The only way I can see to play Chess960 online is to create a challenge, but that doesn't seem to work.

Thanks. On chess.com, it's a little less intuitive, but you gave me the motivation to search further.
1. Click Play, then Computer
2. When the computer game comes up, the only options you have are to change the computer level, whether you play white or black, and whether or not you want coaching on. However, before playing the first move click the "+" button for a (another) new game. When the new game dialog comes up, you then have the option to choose Chess 960.