Join, connect (6)
I believe the answer is:
attach
I believe this clue is a double definition.
'join' is the first definition.
(I know that attach is a kind of join)
'connect' is the second definition.
(I know that connect is a kind of enter)
(Other definitions for attach that I've seen before include "Add or join to" , "Bind, fasten" , "Secure" , "Join to something else" , "Fasten - attribute" .)