Help me please

Help needed to fix spreadsheet.

I'd like to multiply two columns (let's say column A (A1:A706) by column B (B1:B706) so that in column C the answers appear as

C1 = A1*B1
C2 = A2*B2
C3 = A3*B3
etc.

I hope I've made myself clear. I'm a novice at Excel.