(1.17) Any references for making a custom mob?

[feshhi]

I'm pretty new to Minecraft modding. I have been able to figure out adding a custom block that is breakable with a pickaxe, world gen, and make an armor/tool set.

Now I'm trying to wrap my head around what goes into making a custom mob. I wanted to make one that was kinda like an iron golem, where you have to put blocks in a certain placement and then the entity spawns. 

Is there anywhere that explains or shows how to do something similar to this that I can reference and learn from? I've been looking for a bit but couldn't find anything that fit the bill! 

[Luis_ST]

did you looked at the IronGolem?