Whatever operating system you are using to create the USB, you will need to have a Windows 10 ISO, either from Microsoft or your system manufacturer and have a USB drive 8GB or larger (or one with at least 5GB of free space and using the FAT32 filesystem, but using a fresh and empty one is best).
TL;DR
#macOS/Linux
# First try the `bootiso` program, it has options for splitting the WIM for you!
# https://jsamr.github.io/bootiso/
# You need to already have 7zip aka `p7zip` on macOS and Linux, and `wimlib` macOS via `brew` or `wimtools` on Linux