There is an electrical rocker switch in your travel trailer that operates your slide out. I cannot tell you exactly where it is located in your trailer. Just look around and you will find it. Hopefully it is marked as a slideout switch.
The switch has two positions one for opening the slideout and one for closing the slideout. To open the slideout just push the switch towards the open label and hold the switch until the slide out is fully opened. To close it you just push the switch towards the close label and hold the switch until it is fully retracted.