We use the Present Perfect (have+ past participle) for:
#. Actions when the time is not mentioned or is not definite.
e.g. I have washed the clothes. We have redecorated the sitting-room.
# personal experience or changes. e.g. Tom has dyed her hair green.
# recently completed actions. e.g. Tom has just finished typing the letters.
That is very simple :)
And me Present Perfect was very hard, but not now :)
Student or Learner