Hi…,
Welcome.
In Simbrief Dispatch you create a flight plan, then generate flight . This creates an Operational Flight Plan (OFP). Further down that page you Download in FS2020 format. I suggest you download to your MSFS flight plan directory likely :
c:\Users\username\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState
You then Load that plan into MSFS World Map using spacebar/Load/Save.
In the FBW A320, you can also enter the Simbrief plan directly into the MCDU as per How to import a Navigraph flight plan into the MCDU of a A32NX FBW?
Cheers
Ian