I have an a level qualification similar to Cambridge A level,So do l have to start at introduction stage,
I have the same qualification A level with an A in accounting.
However, the foundation level consists of way more knowledge than you acquired for your A level.
So yes it is necessary to do these 3 papers.
Not only that : the foundation papers let you learn a lot about the organisations ,managing a firm and many other small aspects around the place you will be working.
I really found foundation papers interesting and enriching. You should start foundation you may do f1 to f3 in any order, only after completing these 3 papers you will be able to start skills paper i.e f4 f5 f6 ....
its your choice i believe. I didt do the FA1 and MA1...i started from the F1 to F3... these are also foundation papers