1 - Go to Sales menu and select 'All Bookings'.
2 - Select the Booking which you would like to check.
3 - Click on a particular room stay you would like to check.
4 - If the 'Held Until' box does not appear, then the Room Stay is not on hold. On the other hand, if the Room Stay is on hold then the box will appear to clearly show the period of it being held.
5 - From here you may add a holding period if you wish to. To know how to do this, see here.