I cannot create waypoints.
Make sure that the object you are trying to place waypoints onto (in 3D) has a collider attached (does not apply to 2D). If you are not able to create waypoints in the example scenes either, try resetting the layout to default (top right corner).
My object has the wrong rotation when following a path.
This is caused by the model having a different "forward" rotation than the movement script / Unity is expecting. Go back to your modelling application and rotate the model there, or create a new gameobject in Unity, attach the movement script to this new gameobject and make your model a child of it. The movement script will now move the parent instead of your (child) model directly, so you can now rotate the child to the desired rotation.
I would like to let my object start at a different waypoint on the path.
Please use the startPoint variable in the movement script inspector.
On the first waypoint, my object goes back and forth before moving on the path normally.
This can happen if waypoints are placed very, very close to each other (e.g. only decimal places away). Try removing unnecessary waypoints or spread them apart. If you are using a closed loop, do not place the first and last waypoint at the exact same location.
Can I modify the path at runtime?
Yes, however please note that the movement scripts are designed and optimized for pre-defined paths and waypoint caching, not runtime updates. The navMove script is based on Unity pathfinding, as such updates happen per frame and can detect path changes. With splineMove, movement is based on tweens and designed for pre-defined paths specifically. Regardless of the current or one of the other waypoint positions being moved at runtime, movement scripts always need to be restarted (they can continue from their current position) to take this into account.