Excel User form, match date to enter new data or insert new date/data into empty row

Hi,

I'm very new to VBA and coding, and I'm looking to create a user form to enter results from water testing from different locations.
The form allows the user to enter the date the data was collected, the location, parameter and the result as seen here UserForm.JPG

I want to navigate to the appropriate sheet and search for the date entered into the user form, if the date is found, the result is then entered into the appropriate column.
If the date is not found, the form will find the next empty row and insert the date and the data.

Here is what the spreadsheet looks like, Excel Sheet Ex.jpg

I've found and altered code to select the sheet, find the next empty row and then insert the date and data, but I have no clue on how to actually going about looking to see if the date already exists.
I'm thinking I need some sort of IF statement combined with a FOR loop, or MATCH/FIND function, but really I don't have any idea
Any help would be greatly appreciated as well as explanations on what the code is doing

Here is the what I have so far

Please Login or Register  to view this content.

And here is the spreadsheet ALS Sample Results (Autosaved).xls

Give this a try. You may want to replace your text box for date with a calendar control.

Thanks so much for these! And thanks Bernie for suggesting calendar control, I googled it and now have it incorporated in my form