how to use "Then" ?

Actually , I use "then" to explain the 2 processes. For example, u must press N and then u will get the result.... Is it right ? but I saw in somebook use like " is then..." I can't understand the meaning. pls explain to me.

how many ways to use "Then" and how can I use each way of "Then"?

Pls help
Thank a lot
Kee

[RonBee]

I don't know what "the 2 processes" are, but your usage of "then" seems fine to me. You can use "is then", but not in your example.

:)