Hi guys, Im trying to create a company time sheet. This involves the user choosing the week ending date from a dropdown and filling out their hours.

However, when they hit save and its patched into Sharepoint, we don't want them to be able to make another timesheet with the same week ending date. So I guess that I need an error code if they choose a "week ending date that has already been used one in of their previous timesheets. Or alternatively an IF statement that will pull up text saying they have already submitted a timesheet for that date
I have no coding background so I just cant wrap my head around how to go about it. Anybody wanna have a go? Cheers guys