How to change Alternater

Hi ,a mecanic said had repared my alternator,paid 180 pounds for it , 2weeks later same problem ,AA said he never touch it so i want repair it alone . but have steering weel pump in front and dont know how to do it. dont find any manual for help. Do you know of any manual to help change ? Or if you explain i can follow instructions and do it. major problem for now is pump and belts.

Thanks