Plastic screen under the front hanging.

[Beginner]

Hi!
This is my first car and my family aren´t exactly handy people.
Under the front bumper there´s a small plastic screen thats fastened with screws covered in some kind of clip. The whole screen is hanging down and over half of the screws are loose. Nothing is broken, every screw is still there, the screen is whole. I find this to be a part that you don't actually need, but the car is leased and only 6 months to go so I have to fix it.

The problem is that when I try to press the screws on again it feels like the body gives in and are about to break and I don't won´t to screw up the body over a plastic screen. Do I need to worry about that? And do i need some tools to fix this?
It´s a yaris hybrid 2013.
Any reply would greatly appreciated.

[Ben_]

All those little plastic things on the underside of the car are falling off on my car. I bought some zip ties and used a punch to poke some holes in the plastic and 'sewed' it back together