Following a multi level structure, you can load the different quantities, upload the BOM that corresponds to each level / assembly and consolidate all these quantities.
1- When creating the RFQ form, add quantity 1
2- Go to the BOM tab and from the + add the lines. You will need to add
Line item number
MPN: Assembly name/number
Part class > Select Assembly top level for all the lines
3- Then you will need to add the BOM that corresponds to each line item. You don't have to re-import, you can copy from another existing RFQ:
ACTIONS > COPY BOM > ADD YOUR ASSEMBLY NAME / NUMBER > SUBMIT