Connect the Dot Game Grid for iPad

I am a beginner at Unity and I want to make a simple 2D connect the dot game on a iPad. I want to make a grid and put the points at the intersections in the grid but I am somewhat confused on how I should implement it.

I know that Unity has a grid in it but I don't know how I would access the grid and put points on it. How can I access the grid but still make my game 2D? Do I need to write a script to put dots in certain point on the grid or do I just do it manually?

And for iPad game production in Unity can I use a PC to code for it or do I need a MAC to code? Which language is the best for coding on a MAC? Does it matter?

I know have a lot of questions but I would really appreciate your help!

Thanks!