Changing dates based on drop-down selection?

Hi All,

I am trying to develop a worksheet that will adjust dates based on a selection from a drop down box. I can do basic formulas in excel but I am pretty much newbie.

I am trying to get the drop down box in "Revisit Type" to include three selections ("Sanitation", "Spark", and "High Five"). Once the dropdown box is created I want to be able to make a selection and enter an initial visit date under "Initial Visit Date" then have the "Earliest Return Visit Date" and the "Latest Return Visit Date" automatically populated based on this information below:

Sanitation or Spark = 10-30 day window
High Five = 10-21 day window

I am at a loss and any help would be very greatly appreciated. I have attached a sample of the workbook for reference.

Thanks!

I would like to get the DD under Revisit Type in B. The DD in A should just say "Yes and "No", I copied that from another sheet and it looks like it changed. But I am hoping to get the DD with the "Sanitation" "Spark" and "High Five" under B.

Sheet with examples attached, I manually entered the formulas based on the visit type:

Sanitation or Spark = 10-30 day window
High Five = 10-21 day window

I'm trying to get the earliest return visit (D column) and latest return visit (E column) to automatically populate based on the selection in a DD ("Sanitation", "Spark", and "High Five") in B.