Help with Kerdi Shower Curb

I’m redoing our shower after a leak in our acrylic shower pan. Planning on using the kerdi system with the raised shower curb. Ideally I don’t want to rip out my entire bathroom floor to connect the outside of the shower curb to the existing floor tile.

Does anyone know how I would waterproof and seal the gap between the curb and floor outside my shower? I was planning on using kerdi-fix in the gap to bring it together first. Then would tile/grout the curb, and caulk the seam between the curb and floor. Thanks