The present perfect expresses two main concepts:

• Actions that began in the past and continue in this moment; I've played soccer since I was a child. 

• Actions that happened at an unspecified time in the past, once or several times; I've seen this movie many times.

In addition, when we use certain adverbs, we can express more comments, such as:

• For & since: duration of an activity.

• Already & yet: completed or imcomplete activities.

• Ever & never: personal experience.

• Just: an action completed recently.

• All: to express an entire period of time.

Check the presentation below to learn more about this tense.