This Player Mover Character Motor is simply the standard Character Motor script with a few additional methods/changes to make it into a compatible Player Mover.
The Character Motor script it is based off of may not still be used in current Unity Versions, so it is up to you whether you want to use this script or modify a different script so that it can be a compatible Player Mover.
You can add this component by selecting a game object and then selecting from the Top Menu Bar:
Component -> Deep Space Labs -> -> SAM -> Player Movers -> Player Mover Character Motor
or by selecting a game object and using the Add Component menu via its inspector:
Component -> Deep Space Labs -> -> SAM -> Player Movers -> Player Mover Character Motor