HELP: macro to automate a calculation

Hi,
i have never used macros before. but my new job dictates to learn. my task is to calculate the spread of risk based on a share ratio.

in sheet 1 i have the share ratios whose calculations depend on the "sum assured". once the sum assured is calculated the share ratio is calculated to show how much will be given to each party.

in sheet 2 the user will enter the clients each with their own sum assured.

how do i get it to read the sum assured for each client in each row, calculate the share ratios and populate the relevant cells based on the computation of the respective sum assured.


i hope i have explained properly.

please HELP!!!