How do I learn how to tweak my jotforms?

You can modify your forms on the form builder. Just select the form on the My Forms page and click Edit Form.

You can then select each property of the form that you have on your form. Selecting it will show the properties button and delete button per field. 

An example is opening the options for the Email address field. Selecting the form and clicking the properties button shall open the general settings, options, and advanced settings for the specific field.

Feel free to check out the 1st two chapters of the guide of JotForm:

https://www.jotform.com/help/chapter-1-Getting+Started+with+JotForm

https://www.jotform.com/help/chapter-2-Create+Forms

If you wish to go through a more proper learning for building forms, please check out this page: https://www.udemy.com/jotform-training/ 

If you need assistance on a specific part of your form, please let us know so we can provide you details.

Thanks.