Dic/ usages/ now (again, some of its various usages as a 'connector')

now,

As adv:

─ given the present circumstances.
─ used when you know or understand something because of something you have just seen, just been told etc.
─ You use now to indicate that a particular situation is the result of something that has recently happened.

• now we'll have to stay to the end.
• Having met the rest of the family, she now saw where he got his temper from. 
• She told me not to repeat it, but now I don't suppose it matters. 
• Diplomats now expect this mission to be much less ambitious.

Also as adv:

─ You can say 'Now' to introduce information which is relevant to the part of a story or account that you have reached, and which needs to be known before you can continue. (SPOKEN)

• My son went to Almeria in Southern Spain. Now he and his wife are people who love a quiet holiday. 
• Now, I hadn't told him these details, so he must have done some research on his own.

─ You say 'Now' to introduce something which contrasts with what you have just said. (SPOKEN)

• Now, if it was me, I'd want to do more than just change the locks.

As conj:

─ (sub.; often followed by that) seeing that; since it has become the case that.
─ You use now or now that to indicate that an event has occurred and as a result something else may or will happen.

• now you're in charge, things will better. 
• Now you're settled, why don't you take up some serious study? 
• Now that she was retired she lived with her sister.

As sentence connector:

─ a) used as a transitional particle or hesitation word.

• now, I can't really say.

.... COLLINS, LDOCE, COBUILD