How can I download links to room calendars from Google Calendar?

1. Log in to your Google account:
https://accounts.google.com/

2. Open the Google Calendar application.

3. Select a room from the "My calendars" list and click on "Settings and sharing".

4. In the "Settings" window, go to the "Calendar integration" section.

5. Copy "Public address in iCal form".

Google recommends sharing your calendar's public address.
https://support.google.com/calendar/answer/37648?hl=en

6. Paste the copied address to the room calendar in the place where you want to export this calendar.

Do you want to export a room calendar from the Google Calendar application to a selected OTA portal?
1. Log in to your OTA portal account.
2. After logging in to the export and import configuration window, paste the copied calendar address in iCal format.

Do you want to export the remaining room calendars?
Repeat the actions described above.