Unity Voxel game,Cube voxel game

Unity does not have a voxel engine integrated, so you have to either find one that was made by someone else or create a voxel engine yourself. As you said, there are countless tutorials out there which explain how such an engine could be implemented. The terrain generation is pretty irrelevant in your case, so just ignore it.

Note that if you're a beginner, creating a voxel engine from scratch is probably not a good first project. Such an engine is quite advanced and you should have a good understanding how meshes work and how they can be created procedurally. Note that tutorials are not "templates". Tutorials are meant to teach the technology by providing an example implementation. So the goal is that you understand how it works so you can implement it yourself.

So I've given you those two options. So the question is what is your goal. Do you want to learn how to create a voxel engine, then watch tutorials and learn how they work. If you watched tutorials and you don't understand anything, you're simply not ready for such advanced tech. If you're just looking for a ready-to-use implementation, forget about tutorials and look for assets, maybe on the assetstore. However there most likely aren't much assets for free as implementing such an engine requires quite a bit of work and most won't give away their work for free.