[Closed] Mesh Transform

Well, I’m little confused…
is it faster to create instance from existing geometry or create from scratch?
What is the best way to attach meshes?
Is that OK to put every mesh in separate variable and just modify them?
Let say we want to create a LidBox (like Bobo example), would you please show me an optimize and fast example?
I want to create some kitchen cabinets, adding more details, so easy-readable code also is important for me.