If you are the type of hotel that manually assigns the reservations in the rooms on guests arrival then this is functionality for you.

OTA Sync by default assigns the first available room when the new reservation is received.
​
To disable this do next:
​
Go to Settings > General > Reservation Settings > Disable Auto Assigning Rooms > YES and click SAVE

Now all reservations will go here:
​

They will be sorted by arrival so first arrivals will be on top.

To assign the reservation room number, just click on the "Insert" option and assign room numbers.

That's it.