First, force to cover for and that's wrong (7)
I believe the answer is:
mistake
'that's wrong' is the definition.
(I know that mistake are incorrect)
'first force to cover' is the wordplay.
'first' becomes 'ist' (ist resembles 1st).
'force' becomes 'make' (to make someone do something is to force them).
'to cover' indicates putting letters inside.
'ist' going inside 'make' is 'MISTAKE'.
'for and' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for mistake that I've seen before include "Wrong action or judgment" , "Oversight" , "16 down" , "Fault" , "Error" .)