Installing new road bar question..internal cable routing

I’m trying to install some new carbon drop bars on my bike. There is an internal cable route for the brake line (Shimano). Do I just pull the cable from the brake caliper? Or can the cable/housing come off the levers? Very pain in the butt metho d if you ask me. Help!

The housing from the rear, the cable from the front. I think that is what you are asking. The shift cable will of course be in your way.