Welcome to the forum
@SteveM, and more importantly welcome to caravanning in general. Whats the
@SteveM story, are you also new to camping or have you graduated from a tent?
@mikerezny and
@Drover's advise is spot on, but dont stress too much a little bit out in any direction is "A ok", so long as most of the bubble is within the lines. Sometimes it comes down to other not so common personal motivators ... OCD tendencies probably being the biggest. If you feel ok with it and its somewhere within the bubble, then its perfect. Because of the set moulded step heights in most ramps, its impossible to be perfect anyway, level is always somewhere between those steps. OCD people will be the ones with Anderson levels.
My personal motivators are I hate my head being lower than my feet, I prefer water to run off the back of the van and before I swapped out the east west glass sliding shower door for a curtain, I preferred (oddly) the shower door to stay closed when I shower. So I intentionally setup my van front and road side up. Perfectly level only has one (frustratingly impossible) position, the bonus of the intentional out of level position is its dynamic and always right regardless.
As
@Drover suggested setup your van on level ground and stick the 3 way to the drawer bar, using a good thick lump of silicone to use as to level the level on the drawer bar. Mine behind the gas bottle, protected from weather and being stood on The draw bar is the most convenient spot because for us, The Princess can watch it for east west level whilst I drive the van up the ramps, and I can see the bubble from the jockey wheel for north south.