No photos, but I'll try to describe.
The weather striping that is along the door, going up the outside of the A-pillar, can be easily pulled out (and put back in) as it is just pressure fitted. You can pull it out down by where the fuse box cover meets it for easier removal of the cover once the cover is unseated with the opener. The can opener tool is like a screw driver with a hook at its end. The hook part of the opener can easily be "jammed" (without marring the cover) into the groove between the cover and the side of the dash. Using the hook to grab the inside rim of the cover, pull on the opener. The clips are sturdy, they shouldn't break, so don't be afraid to exert some force. You'll know that you have unclipped a clip by a popping sound. You will have to move the opener around the groove to get to the clips...try on the top of the cover and the bottom of the cover. Try to get enough of the inside rim of the cover showing so that you can grab it and pull harder. Pull straight out to pop the rest of the clips. The cover will unhinge at the door.
BTW, I needed to remove the cover to get to the fuse box so that I could hard wire my radar detector. Pulling out the weather striping also made it very easy to run the detector's power wire from the overhead liner (detector positioned on the right side of the driver's visor.) Normally, I would have jammed the wire between the A-pillar and the windshield---bringing it down the pillar then between the dash and pillar trim into the fuse box, but with the 2017 C300 coupe, the fitting is so tight ,this couldn't be done. Pulling out the weather striping reveals enough of the inside of the pillar so that the wire could be snaked from the headliner into the pillar...WITHOUT having to remove the pillars trim, and then down the pillar into the fuse box.