First, you should follow these steps to configure repository space and mount points for your project. Click into the config directory, and click to open "project-definition.xml". Click the "Edit" link to reach the file upload screen, where you can upload your project definition file. Once you have uploaded the file, click save.
If you are making a copy of your site, rather than pointing to your existing repository, you should download a zip of your repository from the GUI of version 1.4. Then point your browser to the root of the v2.0 project, e.g. "http://localhost:8080/my-project/". Next, click the "Workflow" link. Use the form at the bottom of the screen to upload your repository zip file. This takes you to the workflow details screen, where you will see a progress bar while your zip is being processed. When it is finished, the screen refreshes, and you should see a message "Processing complete". Click the "List" link, and you should see all your files and directories. See the usage overview above for details on navigation, management and editing features.
Note that you can use the "admin" user to fully explore your migrated project; custom groups and permissions are not migrated from version 1.x, and will need to be configured in the permissions.xml and groups.xml documents under your project's /config/ directory in order for other users to have access. See the versions of these documents in the sample project for an example.