This set is a 1939 Murphy
A72 we used to have at home in the 40s and 50s.
Tuning is made by a drum dial
running across the top of the set and operated by a cable. It
has a clever system of black squares on the drum, corresponding
to the tuning for named stations marked across the dial glass.
One merely rotates the tuning knob, placing the black square
in the corresponding window and there will be the station of
your choice. At least it was when frequency allocations were
stable but it wasn't after the powers that be decided to change
everything. Worst offender was the BBC that seemingly threw all
their station wavelengths into the air (or should I say ether)
and reallocated them willy-nilly.