My question is about the meaning of the これで in
I've looked to see if I could find an explanation for it, but the many "literal" translations I found all seemed to use the word "now" in their translations in something like
Dewa kore de shitsurei shimasu > Well, I must be leaving now
The idea of これで apparently being translated as "now" doesn't sound right to me but I can't find any explanations or questions about this very basic phrase. What does it actually mean?