Hello I have two questions:

(1)

How to use VLookUP that allows a selection from a list in cell A1 change what is in cell B1 Example:

If A1 = A, then B1 = 1
If A2= C, then B2 = 3

with column A being selected from a list and the table being on Sheet 2 which looks like:
(A) (B)
A 1
B 2
C 3
D 4

(2)

How can I get a selection from a list in, say, A1 affect the options in list B1?



Thanks!!!