The ideal gas equation is an amalgamation of Boyle’s law, Charles’s law and Avogadro’s law and it describes the behaviour of an ideal gas. We can use it to calculate the volume or pressure or temperature of a fixed amount of gas, or to determine the effect of changing these conditions on the behaviour of a gas.
Once you get you head around the units, there is nothing inherently difficult about this topic. But (you could sense there was a but coming) text books give you almost no practice of the types of ideal gas questions that you will meet in the exam.
Use the video in conjunction with your text book to write yourself notes, and then once you are also confident you can calculate the molar mass of a volatile liquid, you are ready to work through the set of exam style questions (relevant for all A level exam boards).