You don't even get to see what happened in the years between ANH and ESB.
The bounty hunter on Ord Mantel was the only thing referenced in the missing three years, and that seemed to be a recent adventure since Han use that as his excuse to leave. Obviously Luke was promoted to (wing) Commander and he learned some more about the force on his own. Vader starting using a new command ship and he figured out who Luke was. And the rebels built a new base, but may have had other bases between Massassi and Echo.
And that's it. And we didn't need anything more, at least for the events of that movie to be understood easily.