Okay so I'm trying to put a homebrew weapon in for my character in a campaign I just started in, but I'm having a problem figuring out how to add a long rang attack to a melee weapon. I'm trying to make it a Warhammer with a rifle built in for my artificer, if anyone knows how to do that in the homebrew function here a tutorial would be appreciated. 

Not possible. Just add a separate rifle and Warhammer to your character sheet and rename them both to match the name of the custom weapon. 

Thank you!