If it's a proper apprenticeship you are doing then I doubt you will learn as quickly as you would like, be patient as has been said it takes time & can be frustrating but is worth it in the long run, no one likes to be on the bottom rung of the ladder but we all have to start there, won't be any different if you give this up & go & start somewhere else.
Having the manuals will help but don't try & be to clever because that will just p*** the operater off (no one likes a smarty pants).
Good luck with it, worth sticking it out if you can as apprenticeships are hard to come by these days.