The instructions below will walk you through how to continue an unfinished tool & update an updatable tool.
Unfinished tools:
If you have not finished a tool, you can continue filling the tool by selecting tools -> and then selecting "unfinished" from the list of the tool you want to continue filling.
Updatable tools:
The updatable checklists you have completed will appear under this menu. By clicking on the "Updatable" menu, you will get a list of tools that you can update after filling.
When you click the row you can update that filled tool.
After finishing that you will find versions at document page.