trying to control linear actuators

Try this modification to Hotwater's circuit to use a single switch for a latching up/down configuration.This assumes the microswitch is set up to be in the Normally Open position when the limit is reached, and NC otherwise.changed the ground control for the relays to use the opposing side relay to prevent a situation where both relays can get energized if the control is hit while already moving, stopping the motor from traveling to the limits.

One clarification:  I am to wire the blocked end of the diode to the COM terminal of the micro switch, not to the NC terminal, yes?  Just so I'm sure.

Yes, the diodes should be connected to the COM of the microswitches. The purpose of the diode is to provide a latching function, keeping the relay energized until the limit switch is hit, and opens up the connection, turning the relay power off, until you push the switch again. A run of the mill 1N4001 diode should do for this application. Without a diode to block the current in the reverse direction, the control voltage would get shorted to ground. So, make sure you get the polarity of the diode correct-