First of all you have 2 classes and only need 1.
This would be like you would have a different cookie maker for each cookie instead of using one cookie maker for all cookies.
The cookie maker is the class, the cookies are the objects, in your case the buttons.
See tutorials | objects on the website.
Remark
This part belongs into setup() please.
When you make a new row in the table you can store the data in each row. Make a 3rd button and store the table on your hard drive using saveTable() command.
See Table in the reference
(Alternatively use saveStrings() command. Not recommended)