Drink stout right to the bottom (5)
I believe the answer is:
lager
'drink' is the definition.
(lager is a kind of drink)
'stout right to the bottom' is the wordplay.
'stout' becomes 'lag' (I can't explain this - if you can you should give a lot more credence to this answer).
'right' becomes 'r' (common abbreviation).
'to' means one lot of letters go next to another (I've seen this in other clues).
'bottom' indicates one should take the final letters.
The final letter of 'the' is 'e'.
'r' after 'e' is 'er'.
'lag'+'er'='LAGER'
Can you help me to learn more?
(Other definitions for lager that I've seen before include "Pilsner, for example" , "Light beer; sounds like camp" , "Lout's drink?" , "Regal (anag) - drink" , "Light beer needed" .)