I highly recommend this class for anyone with an overlocker or who is using one. Individual overlockers were available at each work station but you can also bring your own.
I inherited my overlocker and tried it once a year or so ago and was too intimidated to try it again. The teacher explained the different parts of the machine, how to work with different fabrics and change all the tensions. Trouble shooting and of course threading! I couldn't see myself ever being able to do this. I am so confident with my overlocker now.