what to use??Vlookup or vba?

I am really confused about what to use for this data.I have included the instructions for the task as well.Any help would be appreciated.
i cant upload a sample output right now,i ll try to explain as well as i can.
the aim is to automate the calculations that are required to fill the light green fields in sheet 3.
for example if I enter the name of my trainer against his trainer id in sheet 2..based on the data from sheet 1 the calculations have to be made and the fields in sheeyt 3 have to be filled.
Also please note that the entries with status value "error"should be ignored for the calculations but have to be considered for the bottom table count.

I am sorry if I am wrong but this appears to be an assignment for a course that you are doing. I would NOT be doing you any favours in doing the assignment for you; just so you can get 100%.
To get you started, this is the formula for “Final Out Put Required” sheet, Cell “C3”: [=AVERAGEIFS('Scan Out Put'!D$2:D$397,'Scan Out Put'!B$2:B$397,"OK",'Scan Out Put'!C$2:C$397,"="&A3)].
To have this sheet automated, this is the ‘paste link’ formula for Cell “A3”: [='Trainer Id-Name Mannual Input'!$A2.]
And here is the formula for Cell “H13”: [=INDEX(B3:C10,MATCH(MAX(C3:C10),C3:C10,0),1)]