The consistency of Fondant can vary, with the brand used - apart from adding shortening to soften it or confectioner's sugar to make it less stretchy. I have used Regalice, CovaPaste and PME fondant - with different results!
However what is common to most brands is that if you over knead it - as well as making it too soft, can also cause air bubbles to form throughout! Adding too much sugar to rectify the consistency will cause it to dry out too quickly - hence the cycle never ends!
If you allow the fondant to rest for an hour or so after kneading, and knead it again very lightly - before rolling it out, this does helps. Other factors that you might consider - are atmospheric conditions i.e. room temperature and humidity, and warm hands will also cause it to become soft and sticky.
You say that you are a beginner with fondant - the more you work with it, the easier it gets to handle! I learnt this lesson from my own experience when starting out, and now love working with fondant, so hang in there and good luck!
Hope this helps!