In general you use Present Perfect to express that an action happened at some time before the present time, which is your frame of reference. 

I have taken a dance lesson today. (it's still today, your lesson happened earlier in the day.)

BUT:  I took a dance lesson this morning.  (It is no longer morning but afternoon, for example, so you use simple past tense.)

I have taken dance lessons for the last two years. (You've been taking lessons for a while, and you might not be done with them. The phrasing leaves it open.)

BUT:  I took dance lessons for the last two years.  (You are done, no more lessons = past tense.)

To express that you have done something in the past, and you'll definitely continue with the practice, you use the Present Perfect Progressive:

I have been taking dance lessons for the last two years.

When you want to talk about the point when you chose to start your dance lessons, you NEVER use the Present Perfect, because your frame of reference is completely in the past.  Instead you use Past Tense to refer to that time.

I chose a dance course two years ago. (You were done with choosing; it is no longer happening.)

You can then add that you are continuing with the dancing itself, with Present Progressive:

I chose a dance course two years ago, and I am still continuing my lessons.

Is there a grammar book where can I study? All advice welcome ... 

Thank you so much !!! Present perfect use is more clear !!! Excuse me form my late answer. 

Pir got you covered.  Let us know if it helped.

I am not sure what you want to say exactly.  Do you want to say that at some point in time about say two years ago you started going to dance classes and you continue to do so now ?

Maybe this :  I have been attending dance classes for two years.