From your dashboard you can upload and inspect the progress of your archive uploads.
To start uploading click the Upload a file! button. and drag and drop your archive files into the window and click the upload button.
If your upload is interupted, start the upload again with the same file and it will resume from where it broke off.
Once your archives are uploaded and ready, you can queue them for processing.
Processing may take some time, but you should see the effect within a couple of minutes when the Posts panel starts to display your Google Plus posts.(Some F5 refreshing may be required)