the environment is make part by me excpt the first zone, use this k4 manufacture asset which is a fucking genius https://assetstore.unity.com/packages/3d/environments/ancient-environment-8746
But if you want to start doing things yourself, unity has a tool: ProBuilder that I use a lot, look for packages and textures and with that you can do cool things, l model lara it in devianart, look for "lara croft xnalara" in google, and they will save you many different models, good luck bro