Macro To Transfer Data From 1 Sheet To Another

I am wanting to create a spreadsheet for my stationary orders with some macro's and I have no idea on how to set this up. All the product information will be in Sheet 1 and the Order Form will be in Sheet 2 of the document.

In "sheet 1" we will make a list of all items that get ordered on a regular basis. This can be up to 500 items but
I have given you an example of 6 to play with.

We need the "QTY", "Unit Price" & "Total" in both "Sheet 1" and "Sheet 2" to sum up with a formula

Once the user has chosen the line item they will click on the "add" button next to the line item.

This will inturn take that particular line item and insert only the "Code", "Product", "Unit Price" & "Total" columns in "Sheet 2"
and leaving out the "Page Number", "Item Number" & "Description" & "QTY" fields to Sheet 2 (Order Form)
The user will manually change the "QTY" field on the "Sheet 2" (Order Form)

When the user selects another product and clicks "add" then this new line item will be added below the first line item
on Sheet2 (Order form) and so on.

We will probably only be ordering 10 - 50 items each time so we wont need a huge list on the order form (Sheet 2)