The cassette player mechanism in the 2542 might have been a unit made by General Electric, it shares many common design features of GE portable cassette players from the later 1960's.
The cassette players controls (red arrow) are very easy to use, push the knob to the Right for Fast-Forward - Left for Rewind. Pushing the knob up causes the Tape Head Play Assembly to raise into position and the tape plays automatically.
The green arrow points to the Record button. The record button is pushed and held while the Play button is pushed up.
The blue arrow points to the UV meter. The Recording Level adjustment knob is used to set the UV meters indicator into the "Green" area of the meters scale.