Hi Thanks for using JustAnswer. That is a fairly simple repair. there are no special tools needed other than a #15 torx bit screwdriver. Here is a copy of the instructions. Once the screws are removed there are some clips holding the trim down, so gently apply pressure to the trim to get the clips to release.
Once you have the striker reattached leave the trim off while you check the alignment of the upper tailgate you will probably have to adjust the postion of the striker to get the upper tailgate to close properly. Once you are happy with the alignment then reinstall the trim panel.
I hope this helps, just reply back if any problems or concerns come up.