Scaling a menu bar

I have a menu bar and i want it to go all the way along the top of the screen no matter what the screen size and i want it to take the same percentage of the height of the screen up no matter what size. I do not know how to do canvas scaling much and i am wondering if anyone can help me answer this and also like some videos or something on how to do canvas scaling

Change the canvas scaler component from contant pixel size to scale with screen size. Also change in the rect transform the way the box (the square in the left corner)