Michelle,
You have to cook the mixture to a certain temperature to achieve the right consistency to make the caramel. You might want to get a candy thermometer to make it a little easier. Cook the mixture to 232° to 240° on the candy thermometer. Here's where the soft-ball stage comes in. In the "olden" days, we all didn't have candy thermometers, we dropped a bit of the cooked mixture into a bowl of cold water. The blob of candy (to be at soft-ball stage) should form a small ball but it doesn't hold it's shape when you pick it up.
Hope this helps.

Karol