How do I combine these drawings into one entity?

I want to connect my rectangle thing in the center to the two concentric circles and make one single entity so that I could extrude it later into a part. However, I'm unable to erase the parts of arcs to connect them to the rectangle. How do I do this?

I just got Solidworks a day ago, so I'm sorry if this is a stupid question.

SolidworksParts And Features