primary key - Microsoft Access - Duplicate record issue -

i have issue in microsft access have table detailing amount of money paid client identifier particular month. table has not been set primary key table contains 1 record each payment made rather 1 record each individual includes every payment.

see link clearer picture.

the top table on image have linked example of have , bottom table hoping achieve.

can advise me on best way achieve i'm looking for? i'd grateful if direct me somewhere teach me have never used access before , i'm keen learn.

it seem me top image setup correctly database. if there single payment per month, make first 2 columns composite key...otherwise, 3 columns composite key. wouldn't want have go in every single month , create new columns month , total payment. database growing in wrong direction.

if wanting use bottom image, think excel fine.

also...i don't see duplicate records. having multiple rows same id pretty want in case.