Construct projects are based on HTML5, which makes them perfectly suited for web publishing. This guide includes some useful information to know when publishing...
Hi, I am doing the same with my students! I have used Unity in the past and had them upload to itch.io and it looks like you can upload Construct 3 web games there too. Itch.io is free and a professional experience, they can customise their sites to make them look nice. You can see a guide here: construct.net/en/tutorials/publish-html5-game-itch-io-2363
Do you know a way to make it a Google Site? itch.io is blocked on our school computers...