How to use my own printing head?

The 2.0 tool heads use a CAN bus. There are many articles on the forums exploring existing and new tool heads. Searching for “can bus” on the forums, this is probably a good place to start: Snapmaker2-Controller Hardware Connection
Poking around in CAN Bus

It looks like somebody attempted a solder dispenser for 2.0. There are a lot of good links in the comments.