(This answer is appropriate for many opto sensors, but perhaps not for the one in the original question! Sorry! I'll leave it here in case it helps others.)
These encoders are usually similar to an optoisolator:
The difference, of course, is that a perforated wheel sits between the emitter and the sensor.
The emitter needs to be handled as any LED circuit. You'll need to figure out (from a datasheet, preferably) the LED's forward voltage and operating current. Then you can calculate how much resistance to put in series with the LED.
Since you don't have a datasheet, you'll have to do it with a multimeter and some ingenuity! There are already questions/answers on this site which could help.
Regarding the receiver, there are a few different types of output circuits. Here is an example using a common output type:
simulate this circuit – Schematic created using CircuitLab