Hello Deborah,
Such a great question to bring to the Community, I have a few pieces of free software that will do exactly what you are looking for.
First, you will need some DVD ripping software, you can tap or click here for info on usage and getting the software installed on your computer.
Then for actual video editing, you can use Davinci Resolve which is also available for free. Tap or click here to find the registration page that will lead you to the download page.
You can tap or click here to get started with some tutorials using davinci Resolve on YouTube.