Plan ahead - the learning curve is gentle, but planning something new takes time.
Try the activity as a student before giving it to your class.
Send the student code for the activity to colleagues (coaches included) and have them try the activity as well.
Walk the students through a slide or two of the first activity you do so they gain comfort in how the interface works.
Plan for the activities to take more time than you expect.
Make sure students log in with Google - this way they are able to continue the activity in a future sitting if they do not finish in one block.
Remember during the lesson you can pause an activity or restrict students to a certain set of slides.
Polygraph: Basic Quadrilaterals - students use vocabulary to guess quadrilaterals
Marbleslides: Parabolas - practice transforming parables to catch stars
Polynomial Equation Challenges - write equations to match zeros