How to start with Microsoft Dynamics Nav as beginner??
do you have dynamics nav already installed ?
if no, you could start e.g. with nav 2013. for that goto http://dynamicsuser.net/media/p/312076.aspx
for how to use dynamics nav you could start with https://msdn.microsoft.com/en-us/library/hh173988(v=nav.70).aspx
also i recommend to buy a book about nav basics.
also search on youtube for tutorial videos.