Credits are your module/if you pass the module you get however many credits that modules worth (usually 30 or 60)
Which module are you doing?
how much credit does a 49% equal to? As in you know we have to get 120 credits I wanted to know the credit for this percentage so I could see how much I have left to gain as credits
The final % on the whole module shows how well you did, that will be your grade.
Say you do a 30 credit module and your final percentage is 90%; you will have 30 credits with grade 1 pass (distinction)