To be able to talk/ask about past experiences without a specific date/time attached - EX: Have you ever...? Never have I ever...
Or experiences that have happened multiple times and continue into the present. - EX: Yo he viajado a Canada dos veces.
This is a great tense for talking about life experiences. Have you ever... Never have I ever... etc. Please watch the videos and fill out the tutorial. Disregard anything they say about the "subjunctive". Skip last minute in second video.
This tutorial will help you learn the basic rules for the formation of the present perfect. Be sure to take notes!!!
This video will show you some of the main irregulars. You can skip the last minute of the video completely.