FCP 10.4.8 Shape Mask not following moving person or object

Hi,

I've very new on FCP, having 10.4.8 on a Mid 2014 16-inch Macbook Pro running Mojave 10.14.6. I've been trying to mask moving effects to make it seem it'd go behind a person or object. I've been drawing rough shape or drawing a very detailed cut out of a person, frame by frame or skipping frames. I struggle to have the mask animation be exactly where i put the Control Points. I've checked or unchecked Control Points, sometimes it works fine, sometimes it doesn't, and what's worth is whenever i correct or adjust a frame, previous and next frames are totally off. I've been working on the same few second clip for 3 days and watched dozen of YT videos that don't really seem to help or use more recent versions of FCP...I keep seeing the "Tracker" option, and if it doesn't show, to Sync Clip. Viewer doesn't show Tracker, and - first the project got imported from iMovie - clips don't show up in browser, Sync Clip was greyed out, so i imported the clips, Sync Clip option was available, I synched the clips, but no Tracker option....

Thanks in advance for any help !

Cheers,

Alex