Example: add water density, step 1.
Go back to add water density.
Step 1: add water as material from database. Click Add data>Material property>Step
1:Material, then type water in find material text box, click search. Find water
material you want, then click "Add checked" button. The water is added to you material
tree view. This is shown in the picture below.

Figure 1. Add material property Step 1: Add material from database