If you are looking for help on how to install the app from the AppExchange, check out this article here!
To launch the Formstack app, simply click the App Launcher at the top left corner of your Salesforce.
Once the App Launcher appears, you can scroll through to find Formstack or search for it in the search bar and then click to be launched into the Formstack tab.
When you visit the Formstack tab for the first time, you will be asked for permission for Formstack to use your Salesforce data.
Once you’ve authorized Formstack, you’re all set! You'll be taken directly to the application where you can build your first form.
To learn about building your first form, check out this article here.