Character Falling Through Floor

Probably a silly question, and I might already know the issue but figure asking for help couldn't hurt.

Finished the entire Game tutorial that ran me through creating the small game that I am now working through changing things around for my actual game.

Added my character and setup Mecanim which went pretty smoothly. Updated Game Events and Game Battle Events as needed. But, I started creating my first stage and am running into the issue where the character is falling through the floor.

I'm currently using this asset for the level prefabs: https://assetstore.unity.com/packages/3d/environments/fantasy/polygon-adventure-pack-80585

Here you can see a screenshot of one of the environment prefabs placed that my character passes through:

I'm guessing since it has no collider the character will continue to pass through? Was trying to avoid setting up Gaia for a game that will start with only a couple levels. Is this my actual issue? Or am I missing something obvious? Character does not have issues with the Town or Field scenes provided with the Game Tutorial.

Any insight would be awesome! Thanks!