Today most RV have one or more slide outs. These can be manual, electric or hydraulic. On pop ups and some old smaller trailers they will probably be manual. You pull the slide out by hand from the outside of the rig until it click or locks in place. The rest of the RV will be of a mechanical nature with either electric motors or hydraulics.
All slide outs need to have some maintenance performed at least once a year. The maintenance includes cleaning of the drive arms and some lubrication. Any good dry lube will work. You want to use a dry lube rather than wet to prevent the slide out mechanics from holding onto road dirt. Wet lubes over time will wear away the metal due to the abrasive nature of the road grime it picks up and holds.
Most slides will have the drive mechanism exposed under the slide or inside the RV, usually under the bed. In some cases you may need to search for them. Regardless of your situation, you want to find the access area to the slide drive mechanism and clean and lubricate as best you can.
Make sure to read the instructions for the lubrication that you are using.
Spring is a great time to perform this annual maintenance tasks.