I think if you've not seen the show an opening crawl of like.....
After leaving Tatooine to rescue a young princess in trouble, Obi-Wan and the rebels find themselves cornered with no escape by the evil Darth Vader.
Then just watch episodes 5 and 6
The Reva story arc won't make sense, but it doesn't have to because it doesn't make sense in the full 6 either.
That's what I'd recommend if you've not sat through the show.
It'll probably be epic if you just watch those two.