does anybody know how to hear the sentences one by one in slow-motion ??
this site is very complicated
I don’t think you can on this site, you should choose something to learn from the beginner section, listen and read the text, only concentrate on a short paragraph at first, then try listening with no text and try and figure out what is being said, you should first get an understanding of the foreign text using the dictionary, you will slowly begin to understand, you should learn frequently though, read and relisten to the material you learned, hope this helps, this is a good site but I was also confused at first, track your progress, ask me anything else you need.
yes I know all that, I am a beginner and I started today by the very first lection…but, I just would like to have the solution to put the (in my opinion) fast conversation in the first lection a bit slowlyer, and to have the solution to hear it word by word, sentences by sentences just in slowmotion to hear the word clerly 
However, thanx I thimk I will get in somehow 
You could download the MP3 and then import it into a program like Amazing Slow Downer or Audacity.
@Dinchek - We don’t currently offer this feature on the site. Instead, you can download the audio file then follow solanderdog’s advice above by using another program to slow it down.
Text-to-speech is available on the site, and you can simply click the text-to-speech icon to hear a word, or highlight a phrase a click the button to hear the whole phrase.