What computer operating system?
The following is an Adobe document that discusses Premiere Elements and Timeline markers.
Very roughly - abridged version..
There are 3 types of markers, Main Menu, Scene, and Stop.
Use the Marker area (top left of Timeline) to access the markers.
Marker is applied to place where Timeline Indicator is positioned.
Keep at least a 5 frame distances between the markers.
These markers are fixed to designated positions on the Timeline, not to the clips on the Timeline.
So, if you start moving clips around after you place the markers, you will need to move around the markers correspondingly.
Keep the marker placement to the end of the workflow, just before the creation of the menus.
Please review the above, and then we can get into the specifics.
Any questions, please ask.