For first time installation should you seal your travertine before installing it or do you wait until it is up and seal it with the grout? This is in a kitchen as a backsplash.
You can wait until after it's installed to seal both the travertine and the grout.
Make sure you clean the grout off really well when grouting, so you don't have any grout residue.
If the travertine is really porous, you may want to seal your travertine before installation and again after installation.
I hope this information helps.