How do I go about fixing this IF AND nested formula?

I am new to spreadsheets so I'm not sure if I'm taking the wrong approach to this but basically I want to show a 'rank' when someone has the required number to get that. For example, if someone has between 20-39 points they will be ranked Footman.

Here is the current formula:

IF(AND(L15>20,L15<60,L15=20, "Footman", IF(AND(L15>60,L15=60,L15<100,"Man at arms","Conscript"))))

The formula is returning N/A* saying that it expected two-three arguments but got one. Any help is appreciated, thank you.