Is your Zenit-E the one with the light sensor on the front?
A flat glass plate over the sensor, it looks like a setof black squares under it.
Does it have a meter knob on the left hand side?

There should be a match needle with a ring on the end, looks like a lollipop wiht a hole in.
The light metering needle is just a plain white needle.

As you change shutter speed it should change the metering needle position.

You turn the knob until the match needle is in lined up with the metering needle in the middle of the hole. That's set the light meter reading on the dial in the middle of the knob.

The film speed is set in the middle of the match needle knob, the scale in the centre moves (there's a little pin you can hook your fingernail onto) and you can see immediately there how film speed is related to exposure.