When an option is selected, the user will be directed to the correct evaluation form

Can you send me a URL for a form that when a workshop is selected, the user will be directed to the correct evaluation form.  

Please refer to the user guide: Change-Thank-you-URL-Based-on-a-Condition

Do you want to redirect the user to another form base on the selected workshop option?

You can do this using condition redirect feature.

Example:

in your case, since its another form (evaluation form) you wanted to be redirected after submission, then you can put the evaluation form URL in the Thank you page URL.

Hope this help. Let us know if you need further assistance.