migrating our sharepoint from one network server to another one

I would like you to “migrate” our SharePoint server from one server to another.  This would include:

1.       Installing and configuring the SAME version of SharePoint. (without disrupting current application)

2.       Pointing the new server to the same data set

3.       Insuring that ALL custom work is working on the new server.

I am not sure how to do this, but I have heard this is one of the easiest ways - to “add” a new server  to the existing farm .  Once the new server is there, promote it to the primary server.  Once that is done take the old one out. I am not sure how to do this even.

Would appreciate any help here!