im so confused is jumanji welcome to the jungle a sequel or not to the original?

It's a sequel.  It has different characters, and the game transforms itself into a video game, but it still qualifies as a sequel. 

Suppose to be a sequel but its a joke. First one alot better hands down

In my opinion......the fact they threw the original game into a river........and the movie ends with it being washed up on a beach.............

and the new movie opens with the game being found on a beach........pretty directly implies a sequel was intended , at some point. 

Technically it is a sequel. The game they find in JWTTJ is either the same one that was thrown away at the end of the original (and found on a beach) or at least has similar origins.  A Jumanji experience could have happened to dozens or even hundreds (or more) of other groups of players.  For all we know Jumanji creators sprinkle multiple games around the world or the game transports itself around to the next set of players.