When you login you should be on the my account screen. If not you can get to that screen my clicking on the [My Account] button on the upper left of the tree screen.
On the my account screen click on the [Create or import new family] button.
You will get a new blank tree. Click on the [Import GEDCOM of FamilyScript] button.
Browse for and get your GED file. Then select the "Me" person and you shuld be done.
You can rename the tree on the My Account screen.
