2014 Rules

I bought most of the 2014 rule sets. DM Guide, Player Handbook, Monster Manuel, and most of the adventures. I am the DM and share the content, but when my players went from 2nd level to 3rd level, most the the subclasses are not showing up. I have everything shared. I also tried to search to see what could be wrong, but not finding anything. Any advice? I spent too much money here to not get the full benefits. 

Did you purchase the expanded rules like Tasha's and Xanathar's?  If you have the 2014 PHB, MM, DMG and several adventures you should have 3 subclasses available for each class.  Most adventures won't include subclasses.