So yes i am using a taz 3, and i was wondering if the green sticker thing you put on the bed is required to print successfully?
You will need the green PET sheet or the newer, better PEI option. If you are printing PLA you can print on blue painters tape. Printing on bare glass is not recommended. Part of the glass can come up when you remove the printed part from the glass.
The stresses of the cooling plastic will cause micro fractures in the glass/plastic as it cools and even a tempered glass plate will crack off given enough repeated cooling cycles. That is also one of the reasons the newer PEI/adhesive sheets fail over time.