To print at the libary you simply go to those machines in the copy room, put some money in the machine, then swipe any plastic card that has a magnetic strip to put credit on it.
After clicking print at the computers, go to the computers next to the printer, see which one has your print job listed on the monitor, then swipe the card in the slot on the keyboard and enter a pin.
Note the above only applies for the *fischer library* computers, to print at a computer access lab (remember, there is one within fischer), I think you need money in your extro account. You can put money in it using eftpos at the desk in the fischer access centre or by cash at the margaret telfer building on the other side of parramatta road...