You get it going! (5)
I believe the answer is:
along
'you get it' is the definition.
I can't judge whether this definition defines the answer.
'going' is the wordplay.
I cannot really understand how this works, but
'going' could be 'on' (both can mean functioning or activated) and 'on' is present in the answer.
The remaining letters 'alg' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for along that I've seen before include "From one end to the other" , "For the length of" , "(Going) in company (with others)" , "Lengthwise" , "Sea monster, opposite Charybdis" .)