I too used to be thrown a set of keys and told take that for a company I was involved in some 15 yrs back.
These were not simple aeroplanes like a PA28 or 152.
As MJ says spend some time with the POH and then again sit in the aircraft and working across finger touch everything so you know where and what everything is.
All SEPs are a variation on a theme and its more a case of finding out the differences which you can usually count on one hand.
I would question anyone expecting more than an hour to convert from a PA28 to a C150 as being more interested in your wallet
Pace