Radar information is invaluable for situational awareness and safety. However, you must remember that radar information is secondary to your own observations. You are still responsible for seeing and avoiding other aircraft, even when radar is providing you with traffic information. Radar can be subject to clutter (weather echoes, terrain returns), gaps in coverage, and occasional missed targets. Never rely solely on radar; always maintain a visual lookout.
When the facility provides you with traffic information, respond appropriately. If you spot the traffic, report it in sight:
From that point on, you are responsible for your own separation and navigation until you establish a new radar service or enter controlled airspace under ATC.