Welcome! Are you asking for a "just in case" scenario or do you have an actual problem?

Since I don't have one, I am guessing that the 196 has the same Schwintek slide-out mechanism that our 179 has. That being the case, the answer is, you don't. Manual operation is an emergency action when all else fails. It involves loosening the motors on either side of the slide out on the top track and lifting them up to disengage them. Then the slide is pushed in manually and blocked so it can't slide out since there is nothing holding it in place with the motors disengaged. Then it is a trip to your dealer or other service department to have the cause of the failure diagnosed and repaired.

If it is a lack of battery power, just hooking up the tow vehicle can provide enough electricity to operate the slide-out. Even that should not be needed unless your converter failed and the battery/batteries is/are dead. However, even if the battery/batteries has/have gone bad, the converter (if plugged in) should provide sufficient power to operate the slide-out. Now, there may be an instance where you would need to find the control box and see if there is a code if it isn't working right. We purchased our 179 in December, 2015. In the time we have owned it, we have not had any issues with the slide-out.

See the Lippert site for more information:  https://support.lci1.com/in-wall-slide-out - https://support.lci1.com/in-wall-slide-out

I would recommend reading the owner's manual. One thing you need to do to keep the motors in sync is to not stop the slide-out partway in or out except in an emergency where it is absolutely necessary (such as something stuck in a place that would damage the slide-out if not stopped). That could lead to them getting out of sync. The manual does explain how to get them back in sync if that happens. Best practice is to hold the switch until the motors shut themselves off.