Progressive chart's significance with Natal Chart

I am kind of half a believer of astrology i.e. think it may have some vague reference but am less sure about the finer details of it, e.g. degrees, houses etc.

Whilst I realise that having a natal chart done affords more relevent personal info than just the sun sign, I have now learnt that there is a progressive chart which is also (more?) influential i.e. that takes account of the ongoing alignments. This has greatly confused me. I have had my natal chart done (a while ago now) and there is a facility to read your progressive chart online but I do not know how to make sense of it, i.e. how to read its relevance with the natal chart. Is it the question of degrees that you pay attention to or what?