Around three years have passed between the last episode and this one: enough time for Alicent and Viserys to have gotten hitched,
had a child named Aegon — who is currently a baby — and have another on the way very soon.
Alicent and Rhaenyra are around 17-18 now — a similar age Daenerys and Jon Snow were the
point at which we met them toward the beginning of Round of High positions.
It appears to be that the Battle for the Stepstones has been happening for the
majority of that time, as well — and it's negatively affected the warriors. Laenor, in
the mean time, has experienced pubescence in a significant way.
He's Corlys and Rhaenys' child. We saw him beforehand as a kid in the crowd at the jousting competition in Episode 1.
He's presently around 15 years of age, and he is who Lyonel Solid proposes Viserys have Rhaenyra wed.
It's likewise Laenor we see on the rear of a mythical serpent — named Seasmoke — fighting toward the finish of the episode.