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 see how this works, but
'going' could be 'on' (both can mean functioning or activated) and 'on' is found within the answer.
The remaining letters 'alg' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
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" .)