I have an order form that has two sections for parts to be ordered

example
A: #,B:Part #,C:Description,D:Qty G:#,H:Part #,I: Description,J:Qty

each set of four columns has approximately 15 rows of data,i need to
determine the end of the first column set and enter data into the next.

once columns A1:A15 has it's data got to G1 and start entering data from a
user form.

I'm not sure if an array might work best for this or what ???

thank you in advance