DMX driven scrollers, which most are, respond to DMX channel levels, and the position of the scroll changes with the channel level.
The scrollers themselves will probably have a four pin XLR connector on them, which gets connected through four pin XLR cables to the scroller power supply, which has a mains inlet, XLR4s to plug the scrollers into , and a DMX input connector, and probably an output conector too. You need to connect things up so you have power to the power supply unit, DMX flowing through the scroller PSU, and the scrollers connected to the power supply.
On each scroller will be a dip switch which configures which DMX channel, its probably set in binary, if thats foreign to you, asjk a computer nerd to set it to a channel number.
Then, raise the fader on the lighting desk for the channel you've configured, and your scroller should move.
That should get you going.
