@billyrichrich83
As StoneKiwi has already said, you'll need to provide quite a bit more information in order to get more than general help.
In fact, although you seem to think there's an obvious "long list" in your attachment, I don't see one that would qualify as that. So if there is in that attachment a "long list" that you want to use as the source for a drop down please let us know what it is.
Second, you've already put a lot of work into making this workbook look nice. If I can offer a suggestion: your first priority in designing a workbook in Excel is to make it functional. There are many times when I've witnessed a really "pretty" spreadsheet which still isn't functional, and even times when the use of combined cells and other fancy formatting features gets in the way of functionality.
If you're interested in solving the drop-down on your own, do some research into Data Validation... here's a link that might get you started. https://exceljet.net/excel-data-validation-guide
