How to Use WordPress with Existing Site on a New Host?

How do you use/install WordPress with an existing website already created with WordPress and uploaded to DreamHost from another host. Most of the instructions here assume that your installing WordPress then building a site from scratch. What if you want to use WordPress with an exist website on a new host?

You should probably use a dreamhost one click install, then import the database and reapply any themes and plugins. It might work to restore a site backup, but it might not too, at least without adjustments which may be hard for you to figure out.

First install WordPress then use WordPress migration plugin.
Then take backup for old site then import it.