If we use a modifier, a word or phrase that describes something else, it should go next to the thing it modifies.
Conrad ate a sandwich wearing a blue shirt.
(Here it reads as if the sandwich was wearing the blue shirt.)
Wearing a blue shirt, Conrad ate a sandwich.
(Now we know Conrad was wearing the blue shirt.)The teacher on the blackboard drew a circle.
(The teacher wasn’t on the blackboard.)
The teacher drew a circle on the blackboard.
(The circle was on the blackboard.)
