Step 1: Log in to your Charge Automation account then go to Settings > Preferences > PMS Modification.

Step 2: Turn on 'NEW BOOKING RECEIVED' and save.

Step 3: In your Beds24 account, you can use:

Template Variable http://app.chargeautomation.com/onlinecheckin?bookingid=[BOOKID]&firstname=[GUESTFIRSTNAME] in your Auto Actions to send to your guests.

NOTE: Only new bookings received after turning ON "New Booking Received" will see the pre check-in link.