WAP for given algorithm

In Excel 2007, How do I write the following program :

.1. User enters value in a cell. If it is greater than zero, then the following needs to happen :

.1.aFrom a table 2 values are entered into 2 other cells.

.1.b,Based on these 2 values, there is an existing table which gives us results in a particular column.

.1.c.That column must be copied to another column on the same sheet.

.2..1.a is repeated with the 2 values in the next row which brings us to 1 c where it is copied into a column next to the earlier one.

The problem is that because a table already exists which uses the 2 table values to list another column of values, so i think a wait must be introduced, then this column is copied into another and this process must be repeated with user input remaining constant and just 2 other values taken from a certain table.

This is a real world problem I need to solve for work, please help! I dont know VBA at all, had studied c and c++ a few years ago.