Hi how can i set up my apple watch to my new iphone because it is link to my old iphone and i lost it and i forgot my icloud id and password

You can request an Online Activation Lock Removal HERE.

Or this;

If you can't remember/gain access to the apple id that paired the watch to the phone.Take the watch and it's receipt along with some photo id and any other proof of ownership to an Apple Store and request that they remove the Activation Lock for you.