Try watching the remake (Die Neue These) first, it's a good test to see how interested in the series you are, in terms of the themes and characters. If you like more politically focused stories and don't mind less of an emphasis on the action, you'll probably like LoGH.
The anime series are mostly faithful adaptations of the books, so I'd recommend those; the books do have more details, but the translations are a bit subpar. Haven't read the manga so I can't comment on it. The original LoGH is completed, the remake is still on-going.
Someone made a complete anime watch-guide, here:
https://imgur.com/2kpRjoD
Okay thank you gang .
I want to start legend of the galactic heroes.
Is it good ? Should I watch the anime , manga or the novel first ? Is the story finished ?