help to understand making process

[Dario Folliero]

There's this, maybe It could help

yes i use the move button... i understand that if i select all i can move to center the whole part... but for the primitive part (the stud) i dont be able to move... maybe because its similar to a subpart? 

i try to select triangle, line vertex... but stud move the vertex in preview mode but still in your place.