Trying to set user permissions on a form using vba

I'm creating a form were the user must enter a few conditions before progressing to the next stage. If the user hasn't carried through the procedures an error message should appear and will prevent them from moving to the next stage and message box will appear advising them that they cannot move to the next stage until those conditions are met...based on the error event the user will have to go through alternative steps...and once those steps have been performed and approved then they can return back to the normal procedure (initial steps) to move to the next stage...I hope that was clear. I'm very keen how this can be done using vba or macros...very interested in knowing your ideas in tackling this...I'm a novice with vba so far...always learning something new and interesting about coding, if you have any sample code that would be much appreciated :friends: