How to pass value from one cell to another
 

Suppose I have a if function in A1 who is test ing for a 1 2
or 3 input in A2 Cell

In case 1 I want to start a function in B1
In case 2 I want to start a function in B2
In case 3 I want to start a function in B3

Second question is; how do I pas a value TO another cell
Like in A2 Cell if B1=1 (or wharever) then B3 gets value B2
It might be rather easy, but I can;t find the solution on the moment

Thanks for the help

Grx Rolphe