hi there! there is a button at the top right of a phone and when you click it, it becomes a laptop. that way you can see both, how it'll look in mobile and pc.

second. each element if you scroll to the bottom, it has the settings called mobile: auto/manual. when using in auto it will use the same settings as the pc and it can look weird sometimes, i recommend you to put it in manual and put the phone view and edit the height or width there until you're satisfy and do the same with the pc view. if you have any other doubt, you can send me a dm if you want ^^