Prototyping Quiestion

I’m learning how to create a prototype in Figma and I have two questions.

First, I need to make an interaction which when I click a button (any button) on page 1, it automatically needs to navigate to page 2. I did the part where the button turns blue when I click it. But I don’t know how to make the page change from page 1 to 2. 

Second, when I click a button(one of the small squares), it needs to change it’s color and the long button needs to change it’s color too. (Without any trigger on itself). I did the part where the small button changes it’s color but the second part is kind of difficult.

Could you give me instructions on how to do these? Thank you very much!