Starting from zero, any guidance?

So I am completely new to blender, but if it will help me any I have tons of solidworks modeling experience. I’m looking to make something for my wife, and what I have in mind is a skull with some sort of pattern or extruded bits to it, but I literally have no idea how to do that or really anything. I am looking to learn Blender more in the future, but for now, I just wanted to see if anyone had any guidance or suggestions on where I could go to learn that specific part of Blender. I already have a skull model I downloaded, I just need to know how to add to it. There are a lot of these type skulls on thingiverse etc that I 3D print for my wife, now I just wanted to make them custom for her and upload those for others to download. Any help would be appreciate, thank you so much in advance for any help

Hi and welcome to BA,
I know almost nothing about 3d printing but if I understand in the correct way your question you can use different techniques to achieve what you want: displacement, sculpt, etc.
Below just 2 quick examples from Blender Secrets (this guy has A LOT of very quick tutorials that you can also use just to see the workflow that could fit your needs):