Start with half a beer with a gin to follow (5)
I believe the answer is:
begin
'start with' is the definition.
(I've seen this before)
'gin to follow' is the wordplay.
'to' means one lot of letters go next to another (I've seen this in other clues).
'follow' becomes 'be' (I can't explain this - if you can you should give a lot more credence to this answer).
'gin' put after 'be' is 'BEGIN'.
'half a beer with a' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for begin that I've seen before include "Institute" , "Israeli statesman" , "Monachem --" , "Israeli prime minister who shared the Nobel Peace Prize with President Sadat" , "Make a start" .)