Choose Layers > Loadings > Live (Reducible) Loading > All Loads Plan.
Double click the Area Load tool ().
In the Default Area Load Properties dialog box:
Change Fz to 2 kN/m2 and click OK.
This tool will now draw area loads of 2 kN/ m2.
Define an area load over the entire slab by clicking four corners of a quadrilateral and then typing "c". This shape need not match the slab’s exact dimensions, but should cover the slab.