1. Make sure your home wave is the current wave and do a page reload.
2. Click the 'Share' button
3. Go to 'Your Wave Admin' tab
4. Click 'Load'
5. Double click the wave you have been invited to and drag it over to the 'Accept invite to Wave' box.
6. click 'Save' and refresh the page. Your current wave will now be this wave and you will be able to switch between waves by using the drop down box at the top of they page.