How to assign VBA code to user form controls

Hi all,

I've created a user form that has a single text box which takes 6 characters in it, this box has been assigned to "Site ID" e.g CE0001.

In the same form I have three tick boxes that identify three wireless technologies which the user is to tick for each technology that is present on the site in question e.g G09, U09 and U21.

They also have to tick up to 3 boxes should there be one two or three sectors on this site referred to as Sector A, Sector B and Sector C, some sites will have one sector, some will have just two but most will have three.

Based on these input combinations, should the user press the enter button below then the VBA will unlock some hidden tabs that correspond to each technology and pre populate a range of cells in the tabs with a text string which is a combination of the Site ID + Technology and Sector ID e.g CE0001U09A3.

If I can get some pointers on how to assign the text string based upon the user inputs I will be very happy. I can worry about un-hiding the tabs at a later time.

Any help would be greatly appreciated.

Many thanks in advance.

Pedro