My K-1, (form 1065), has five entries (by codes A, AA, AB, AC, and AD). Turbo Tax has only three windows to enter code and amounts. How do I enter the other lines?

You didn't mention which box on the K-1 had the five entries, but if you enter information in the first two lines and then start entering on the 3rd line, a 4th line will then display on the screen.  When you start entering on the 4th line, then a 5th line will display and so on.  See the sample screenshot of box 20 for a K-1 (form 1065).