Go to the page https://portalcientifico.upm.es/en/. Click the Home button in the top right corner:

Enter your credentials in the SIU forms:

You are now inside the Portal Científico. You can choose the traditional version of your profile: iCvn or the new version of the interface: iCvn 2.0:

If you are unable to access, please contact this form, sending the different email addresses you have at UPM.