It is possible to use the checker tool from the Ouriginal website
Once you are on its website, you will have to choose Universidad de Lleida in the listing and select "Sign-in via institution" so you can enter using your user and password.
Once you have done it, you will see the option to upload the files that are to be analysed.
The analysis feedback can take a while. You will receive notification in the UdL email to let you know that the analysis is ready and available in Ouriginal.
In case of doubt, you can check this link with the official Guides & tutorials