Where the sites on the original hosting provider DNN sites? Did you get backups of the databases and the files? Having this information will help us to help you.

Installing modules is done by logging in with Host credentials and going to Host->Module Definitions. Depending on your skin you might have a link at the bottom of the container to install a module but at minimum you should have an drop down menu somewhere around the container title that will give you the option to Install New Module. You can also put them in the Install/Modules directory and they'll automatically show up at the bottom of the Module Definitions page.

I'm going to ask one of the full forum moderators to move your post into one of the more general forums. You'll have a better chance of getting help there.