Well done on getting most of the stair done then. I am not sure what you mean by “half landing”. If you mean the horizontal beams at the top of the satair that are part of the stair macro they are welded to the stringers by the macro.
Any other landing will presumably be made from normal steel beams so simply choose a suitable joint from Connection Vault and apply that (e.g. Clip Angle or Single Sided End Plate). You can freely add additional joints to members created by macros you just can’t change the original member outside of the macro.
I hope that helps.