Manufacture an Asset

Hi - I’m hoping someone can put me on the correct path, or at least start of the path!

I need to manufacture an asset, that will not be for sale.

I think I understand the process to manufacture an item that can be sold, but am a little unclear as how to make one that will not be sold (item>>isfixedasset = Yes)

Would it follow a similar process? I have tested a few things, but right off the bat I get a roadblock when I create a BOM as the item has to be a maintain stock item.

ERPNext 13.11.1
Frappe 13.11.0