What engine are you using? Unity? Unreal? Godot? Etc.
In unity you can switch build profiles to web and that should work.
Viewing post in This is my first game jam where I managed to submit a game.
You have to upload it to your project page. Make sure to set your page to html5 and not downloadable. Then, upload the zip file of your web game and make sure it is the first or only one in the download section. There should be some options about how you wanted embedded in the page, so play around with them.
That should get the game up. I just went through it and it worked.