Each attendee that enters the classroom automatically gets access to their own lab. As the event host, you will be given access to a lab similar to the ones your students get. Use your lab to demonstrate things to your students that they can later perform in their own labs.
Your lab acts just like any other section in the classroom. When you want to present your lab to the students, make sure "Present Mode" is on and use the navigation bar on the left to access your lab.
You can open and close additional tabs (via the + and x buttons respectively), and type in the console (assuming you're using a Linux lab). Your students, however, can only view your lab. Since it's simply a matter of navigating to another tab, jumping between your lab and theirs will allow students to quickly see reference solutions you provide.
At the top navigation bar, the cog-wheel icon allows you to restart your lab or to show some info which will allow you to connect to it locally.
Accessing your lab outside of the classroom interface
You can easily access your machine's publicly facing interface and connect to it. Do this by clicking the cog-wheel and then clicking "Connect From Local".
An example for when this can come in handy is if, let's say, you are running a workshop with a Jupyter notebook. Assuming your notebook runs on the default 8888 port, you can copy the machine's public DNS address to a new tab in the browser and view the notebook at e.g.
http://ec2-52-29-70-104.eu-central1.compute.amazonaws.com:8888 .
Students, by the way, can do the exact same thing on their labs and you can also send them the same link you're using so that they can see web-interface changes in your lab as you make them.
TIP: If you're running a Linux lab and would like to connect to it via SSH using your own ssh key, you could add your privately generated key using Strigo's web interface, and then use the DNS address, user, and your generated key to connect to it.
At any given moment, you can replace your lab (and other students' labs) if things go awry. Click here for more info on lab management.