The FE mesh can be generated or re-generated by go to Analysis>FE Surface Meshing>Regenerate Meshing. This will run the mesh algorithm and producer the FE mesh for the whole model. If no mesh exits, this option will create the initial mesh.
If a mesh has been created, but the model geometry has been amended, then the original mesh will be deleted and a new mesh will be required.
If a re-mesh is required on selecting the Analysis option, the mesh regeneration will be carried out automatically, before giving the analysis options.