You can create a new Form by going to File
or Click New Form
icon in the main toolstrip.
As soon as you create a new Form it will be added to Forms window on the left, that is where you can delete it if you wish.
You can close your Form and re-open it again by double clicking on it in the Forms window.
You can Rename your Form by clicking on it, going to Properties window and change Name property, Form name will change on save.