Assuming that with the "latest version" you mean the 1803 version released this week, download the .iso from https://www.microsoft.com/software-download/windows10 , mount it and run setup.exe. That should be all.
The time to download depends on the speed of the internet connection, the time to do the update depends on how fast your PC is. A time of 1 to 2 hours is reasonable. Don't interrupt! If it's a laptop run it with the power adaptor!
hi, i'm having a bit of a problem updating windows to the latest version.
i'm trying to update it using the windows 10 upgrade application, and it is so slow. can i download the ESD file separately from another place and put it in the download folder of the windows 10 upgrade application?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic