In the hole is a grub screw, use the 2.0 hex bit that came with the Snapmaker screwdriver (the middle size one, smaller than the one you use to change beds & tool heads).
The hot end then slides out the bottom of the module and you can gently pull the cable out and disconnect.
It’s shown in the video on this thread - https://forum.snapmaker.com/t/is-there-a-guide-to-replacing-the-hotend-for-the-s2/12654/3 from about the 0:35 point.