Hi Rik,

You have to change the default setting that says "use an Odoo.com account".Open up the extension, open up the left navigation bar and click on "Synchronise":

Now click on the "Sign in" button:

A new view will open where you can give in the IP of your Odoo instance. Fill it in and click on "Next":

Now choose the correct database, give in the username and his password and click on "Login":

You're now ready to book timesheets through the Chrome plugin on your own Odoo instance.

Regards,Yenthe