Once we've got a matching or close-match panel, the job is mechanical: disconnect the opener arm, run the door down manually, pull the end hinges off the damaged section, slide it out, and set the new panel in with the same hinge and roller hardware if it's not bent. If the dent came from an impact hard enough to crack a panel, we check the roller track on that side too - a bent track from the same hit is common and easy to miss if you're only looking at the panel.
On insulated steel doors, we also check that the new section's weight is close enough to the old one that the torsion spring doesn't need rebalancing. Most single-panel swaps don't change the door's overall weight enough to matter, but on a double-wide door, even one heavier or lighter panel can throw off the spring tension and leave the door hard to lift by hand if the opener ever loses power.