2D Game. Screen, Camera and coordinates.

Hello.

I developing a card game where camera shouldn't move. But when I start the game some objects were outside of the screen. However on camera preview everything was ok. I belive that this issue occurs because changing the screen resolution.

When I created GUI I used coordinates which depended from screen resolution.

In my card game I have few cards, let's say 10, which should arranged in a row. And each should be visible, i.e. fully visible on the screen. Cards can be scaled as so as needed. All cards have same size.

I belive that I need the dot located in top-left of the screen and stay visible in all possible resolutions. Then naming this dot as null I place all objects relative this dot.

How to correctly solve this problem?