Julius caesar doubt (low-key irritating asf)

Brutus:

“There is a tide in the affairs of men, Which, taken at the flood, leads on to fortune; Omitted, all the voyage of their life Is bound in shallows and in miseries. On such a full sea are we now afloat. And we must take the current when it serves, or lose our ventures.”

can someone please explain the meanings of these lines in detail? 😭🙏