Assuming your Simbrief plan has been accepted, so it's shown in green in the GSX menu, you need to be sure you are using one of the more advanced VGDS which supports displays large enough to show those informations.
They are the T1-42 (most complete) or the T2-24 (with reduced info) and there's nothing you need to add manually, all the relevant information will be pulled from the active plan on Simbrief.