Importing a CAD geometry and using Mold Mesh tool is only valid for sequences that includes Cool (FEM).
You can also right-click or double-click Create Mold Components.. in the Study panel and select Add CAD Mold Component.. (number 2 in the Figure 1).
Figure 1: Create Mold Components options within the Study panel.
You can also double-click Create Mold 3D Mesh... in the study panel, if Mold component is not ticked (see Figure 2).
Figure 2: Create Mold 3D Mesh
The mesh parameters are automatically set, however you can customize them. The Global edge length is the main parameter to play with.