I'm not sure exactly what you are saying, but are you looking for the parts
for a Star Wars MOC?
If so, do you have a list of parts (partslist)? If so, create a Wanted List and
add the parts to it, then purchase the parts you need. If not, then can you show
us the MOC and we might be able to help.
If it's your own MOC, then I would suggest you work out what parts you need.
Have you modelled it in Studio already? That can export a partslist that you
can make a Wanted List from here on BrickLink.