Asking for assistance to write an appeal letter

Hi all ,
I am a student at the technical academy here in dk , bachelor software development .
Last week, I went to my project exam , and got a grade which I am dissatisfied for ,because I think its unfair ,as the work I have done worth more than the grade I have been given .
My project was about building a web application with a number of useful functionality , along with a project report where I covered all the materials I learn during my previous semester at the programme.
Actualy , I was not given the time the examiners to explain the cource code of my program , there was focus only on a part of the project report ,which is testing . and no question about the program code nor other parts of the report , system development methodoly etc etc
I asked the administration and they say that I can appeal against this given grade , if I support it with good arguements etc.
I will appreciate if any can assist me with writing a formal appeal againt the grade , to request reviewing my project again

Kind regards ,
Marwan