I am using altium for first time for my little circuit project. My layout start showing these weird capacitor looking things in PCB layout. What exactly are they and what are they used for and how do I disable them to show up on layout?
That comes from running a design rule check with no traces routed. It is showing you the rubber band connections that are not complete.
Go to Tools->Reset Error Markers to get rid of them. The rubber band lines will stay but the 'capacitor' error markers will go away.
That's a broken net. They will disappear as you route traces and run a DRC.