On the Calendriers page, select a calendar you like.
Click Sélectionner.
If you are not logged in to WebCal.Guru, you will not be able to modify subscription settings and you will have significantly smaller selection of calendars. In this case, jump directly to Step 4.
Adjust the subscription settings if needed and click Ajouter à mes calendriers.
You will be taken to Mes calendriers page. On the calendar you just added, click and select Copier l'adresse dans le presse-papiers.
Log in to Outlook Live Calendar.
Click Add calendar.
Go to the empty field with Example... and paste the clipboard contents there. The result will look something like https://www.webcal.guru/....
Enter the Name, Color and select a Charm for the calendar. Outlook will not use the color and name you may have set when subscribing the calendar. Finally, click Import.
Updated 8 Feb 2023