Flight Instructor reported a near miss with two aircraft while following an ATC heading clearance on a visual approach during a training flight. The instructor took control of the aircraft to maneuver away from the first aircraft; then maneuvered away from the second aircraft; followed heading instruction from ATC then returned for a landing.

Narrative

We had received instruction from the tower to proceed to a straight in final for runway 6. We could see another aircraft on the ADSB screen on our left also approaching final and our paths were converging. The other aircraft was on a practice instrument approach on RNAV 6. Tower kept telling us to turn left; but we did not turn left even though we could not see the other aircraft; we could see them on the screen and chose not to turn left until we could see it. Tower once again told us to 'widen your turn to the left' and at that moment we were able to see the aircraft next to us within 500' and converging. I; as the instructor; took over controls and made an evasive turn to the right. I then immediately saw a 3rd airplane right in front of us with our paths converging. I saw the other airplane turn to the left and we continued turning to the right. After communication with the tower that we had a near collision with two separate aircraft; the tower told us to fly south west away from the airport and then turned us back in for a landing.