haven't seen any of the movies,should I start with this or Battle Royale

Fanboy much? I've never heard even the annoying people claiming rip-off describe the movies that way. Hell, most that like battle royal admit battle royal 2 was bad, and the reviews show that.

Also, you keep mentioning remakes and originals. Hate to burst your bubble but there hasn't been a remake yet. Fanboys are usually delusional though, so my expectations are never very high when trying to discuss films with them.

It really doesn't matter if you start with Battle Royale or BR2 first, because they both work as one-offs.

BR is about the Deathmatch whike BR2 is about the revolution that ensues in a dystopian society when the games are finally dismantled, exactly like in the HG series.

Start with "Hunger Games" film. If you like it continue with the other films in the series.
Avoid "Battle Royale" films at all cost.

Whichever. They're separate universes with no connection other than Hunger Games getting some idea from Battle Royale.