What is the most practical way to force the user to give input in an order

Question

Say you want the user to input the numbers 1, 2, 3, 4, 5. But they must input one first then 2 ect receiving a message that they must pick the lowest number and referring to which is the lowest before continuing. I feel like I'm explaining this bad.

Answer 1

Users are the most unpredictical species in the programming world.

I usually try to avoid requesting any order from them.

If you have to.
Do a lot of validation, and give them a lot of feedback messages.
Can you ask them to put everything in at once and order it yourself ?