Can not use properties of rigitbody2d

Hi, everyone. I was just watching tutorial how to make a 2D game (tutorial from brack**s). And there was a JS script:
rigidbody2D.velocity.y = speed;
So when I tried to write this (in c#), VS told me that i can’t do it, because that’s not a variable, So how can I fix it? Or I need to use something else to change position in Oy? (if here was some grammatical mistakes - sorry, english for me is foreign language)

in c# you there is no get{} method for vector components. set velocity.y by assigning velocity with vector3 constructor new Vector3( velocity.x, yourY, velocity.z )