Create objects move along the bottom that the character can't touch?

The documentation that Unity provides is extremely helpful. I would take a step back, look at what needs to get done, and get a general idea of what functions you would need that Unity provides. Fundamentally, what you need is:

• Transformation of your objects position.

• Rigidbodies (Which I recommend for player movement 100%)

• Ability to create and/or destroy objects.

• Collision/Trigger detection.

• Finesse of integers.

Everything you are looking for exists in the Unity documentation. Find what would be relevant to what you need to accomplish. The only thing is the "Finesse of integers." which is simply how you're going to keep track of lives.