Solidworks Thread Feature

 

The Thread feature has Type, Size, Thread Method configuration. Under the Size there are some given configurations changing the profile. What if I have any random size cylinder dia or boss or hole? Will the cylinder dia matter? As from the image my cylinder boss is 2 mm but I have give M1.6 M2 M3.5 M4. What does the override work? How are all connected? When should I use cut thread or extrude thread? How should I choose die or tap?