Swap is the overnight or rollover interest for holding positions overnight. The swap may be either positive or negative.
Swap addition/deduction to open orders is carried out from 23:59:00 to 00:10:00, trading platform time. So the swap will be added/deducted to all orders which were open during the period from 23:59:00 to 00:00:00, trading platform time.
Contracts with an expiration date. In the case of trading those contracts that have a limited period of trading (expiration date), all orders executed on one contract will be closed by the last quote.
You can look up swaps long and short on the FBS website. The trading terminal automatically calculates and reports all swaps on your open positions.
Please, kindly be informed that for the weekend rollover, the Forex market books three days of interest on Wednesday.