Followed a soundly simple design (6)
I believe the answer is:
chased
'followed' is the definition.
(to chase someone is to follow them)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for chased that I've seen before include "Hunted" , "Decorated metal with engraved or embossed work" , "Went after with the intent to catch" , "followed" , "Engraved; rushed" .)