Stops to get some things from the builder's yard (6)
I believe the answer is:
blocks
'stops' is the definition.
('block' can be a synonym of 'stop')
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for blocks that I've seen before include "Three-dimensional shapes with six sides" , "Impedes" , "Prevents the movement of, gets in way" .)