Re: difficult sentence
Adel, please write the full sentences without your questions in between.
You can repeat the sentences with your questions under the original text.
The part about "pull up" changes meaning when you see it goes with "the surveillance camera" -- in that case, it would mean "make the monitor display what is being recorded by that camera."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.