im new to quickbooks and mtd 

i sell new goods that are 20 percent vat

i also sell second hand goods that i use the global sceme that i pay 1/6 vat on the difference between sales and purchases.  ive used a split on my transactions but i cant work out how to use the data for the vat return. or is this software not suitable for my needs. im really confused over it all 

appreciate any help