To find what you seek ................................................................... i.e. to get a balloon afloat - which you need silk or rubber for the actual balloon ...
You must watch me carefully ............................................................. i.e. you can't get silk - so you try jumping on the bed, and see that the bedsheet is elastic ...
Or you could just guess .................................................................... so, since all you can get is elastic rubber, and you can't steal your own bedsheet, you steal the spare.
Am I right? *crosses fingers*