I hope you are well today and thank you for your question.
1. How to limit the number of posts on the main page to the number of lines, for example: if i give 3 lines – for different resolutions it will be a different number of posts, eg. phone 3×1, tablet 3×4, pc 3×6.
Currently you can only control how many posts should be displayed on home page by setting the value for the WordPress option "Blog pages show at most" in the Reading Settings on the following path.
Admin Area -> Settings -> Reading
To control the display of posts on different devices you will have to hide the posts developing some custom CSS code using Media Query to achieve this as described on the following pages.
Do you mean on phone 3 post should be displayed and for tablet and pc 4 and 6 posts respectively?
2. Between these lines to insert the field over the entire width of the page (eg. Advertising)
To achieve this you will have to overwrite the Pinbin theme index.php file in your child theme and add the Advertising field code on line number 29 in that copied file.