If statments to inventory analysis

Hey

I have a datatabel on sheet1 and want to do some calculation on sheet3.

case:
hey.jpg

I want to have an if statement that says:

if clientid (starting in C3) = 600 then places customergroup (starting in I2) in sheet3 starting in B13

if clientid don't = 300 then it should not be placed in sheet3

this if statement should be like if C3 = 600 then places I2 in B13 or don't show in sheet3

next line if C4 = 600 then places I3 in B14 or don't show it

This if statement should be run until there are no value in C or I (end same time, but i don't now when it will it will end, because it can chance over time)

Can someone please help me?