The events at the Kilika Temple have finished and Yuna got her second Aeon, Ifrit. You’ll need to return to Kilika now and if you took care of Lord Ochu, it should be a pretty easy trek back through Kilika Woods. Once you’re back in Kilika, head to the second screen and on the southern dock is where you can leave for the next destination, Luca. Upon regaining control, you will be in a room with the Besaid Aurochs and some other NPCs. On the left side of this room, partially obscured, will be a chest that contains a Hi-Potion. Exit the room and you will see O’aka again, where you can give him some more gil (this is cumulative with the previous donation, if you gave him some).
Save your game, if needed, and head up to the deck of the ship. Right next to where you pop out is another door, leading to the bridge, so go in there to find Al Bhed Primer Vol. V on the ground right behind the person steering the ship. Near the back of the ship is a scene with Yuna and some Luca Goers, and on the upper level will be another scene with Wakka and Lulu. Note you can continue heading to the upper level to get more scenes with Wakka and Lulu, which will give you some insight on things.
The primary goal of this boat ride, though is learning the Jecht Shot, a skill for Blitzball. Before doing this, it’s a good idea to save your game, as you only get a single chance at this (for now, at least). If you don’t happen to get it, then you can reset your game to try again. Locate the blitzball near the front of the ship and approach it to trigger the cutscene. You will get a brief tutorial on what you have to do here, but the basics is to press the X (Playstation)/A (Xbox)/B (Switch) button with the direction on the D-Pad, in correspondence with the directions in which the words appear.
You don’t have to get all of them, but the words do come pretty fast and the game will give you an opportunity to practice a little bit before doing the real thing. What makes Jecht Shot so powerful will be seen in a little bit, but getting it will also unlock the Striker trophy/achievement. After a short scene following your success, approach Yuna for one more scene, then you will eventually arrive in Luca.