In SQL Editor window:
Click add table icon
Add fields and qualifiers for these fields
In SQL Editor window:
R-click table | Send to SQL Editor | Create statement
In SQL Editor window:
Select database
Database | Reverse Engineer
Follow the steps, taking the defaults until get to table selection
Select tables you want
Finish
MySQL Workbench creates an EER diagram on a separate tab.
With this tab open, on File menu, can:
Save model (as .mwb)
Export as png or pdf
Forward engineer -- make a script to create tables shown in the model