You can connect your student's CodeCombat and Roblox accounts from your Teacher dashboard. To get started, you will first need your student to provide you with their Roblox user ID.
This is found by logging into www.Roblox.com and clicking your username at the top right of the page -- then the user ID will be located in the URL as a string of numbers as shown circled below.
Once the user ID has been provided, you can connect the accounts for your students from your Teacher dashboard. First navigate to the class view for your student, and then click their name. You'll find an option at the bottom of the pop up window to connect the student's CodeCombat and Roblox account by entering their user ID into the field and then selecting Connect.