In Set Analysis Requirements Page 2, selecting Yes for the question Use Automatic Mesh Size Estimation? will enable the Automatic Mesh Size Estimation dialog.

To generate the tool mesh, click Generate Tool Mesh. It will display all the element sizes for each metal extrusion assembly disabled. This has a slider bar for every component to control the mesh size. As the slider is moved you can see the element sizes.

Click Mesh to generate a tetra mesh for the selected solids.