Newbie question, how to auto-fill a field based on another field
I know this is super simple, but I am quite new to Filemaker and work at a school without a tech person. I'd like to save money by not hiring our consultant to create this field.
We have a database to track auction items. These items fall within specific categories, i.e.
100: Clothing, Jewelry & Accessories
200: Art, Books & Music
300: Pamper Yourself
And so on.
These are in a value list that are a drop down menu for the field called Donation Category. I created a field Donation Item Number. It would be great if this field could take the numbers from the first field and auto-populate. So, if I enter a hand-sewn jacket as an item, choose the category 100: Clothing, Jewelry & Accessories, the Donation Item Number would fill in automatically with 101, and so on. The list goes all the way up to 1400: From the Faculty.
We aren't so large that this couldn't be done manually, but it would be super snazzy and a good time-saver as we use volunteers for all of the data entry.
Thanks for any help from an underpaid, overworked and confused non-profit worker.