If you would like to install the ToutApp Package into their Salesforce Sandbox package you can follow the instructions below.
1) Click here to navigate to the AppExchange
2) Click on "Get It Now".
3) Click "Login to the Appexchange". If you get navigated directly to installing the package then you will want to sign out of Salesforce and try again. You should be taken to the login screen
4) Go to the URL in the address bar and delete "login". In it's place enter "test". Click enter.
5) The address should now show "test.salesforce..."
6) Now Sign in. Make sure you are using your Sandbox credentials as they are usually different than your regular Salesforce credentials.
7) From here you can use our regular Admin Guide to get everything set up. Select what users you want to install the package for and then start from step 2 in the guide.
NOTE: These steps for installing from the Appexchange into the Sandbox environment have been provided to us by Salesforce help center. You can see the instructions if you look at the "Note" at the top of Salesforces's Install A Package article.