Two beginners phone in drink order for sexton (4-6)

'sexton' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?

'two beginners phone in drink order' is the wordplay.
'two beginners' means two replacements for 'beginner'.
'beginner' becomes 'L' (as in a learner driver with L-plates on their car).
'beginner' becomes 'L' (as in a learner driver with L-plates on their car).
'phone' becomes 'ring' (to ring on the phone).
'in' means one lot of letters goes inside another.
'drink order' becomes 'beer' (I can't justify this - if you can you should give a lot more credence to this answer).
'l'+'l'+'ring'='llring'
'llring' placed into 'beer' is 'BELL-RINGER'.

'for' is the link.

Can you help me to learn more?