Different screens, fixed UI, dynamic map

Hello there, I'm trying to make a small game but I'm having a hard time with supporting different screens resolutions the picture bellow is what I'm trying to achieve, I'm trying to make a side bar and a bottom bar, these bars should always be there and should always scale to the screen size, the rest of the visible area is the map for the game and what ever left of it should appear in the are, how do we achieve such thing?

the bars are completely UI elements, when I change the screen ration they are being cut