Having done this on a new machine recently...assuming that you are doing a completely fresh install.
Plug in the SSD to the first SATA port.
boot the machine into the BIOS setup.
Set USB as the first boot device.
Reboot with the W10 USB plugged in
Now you'll get Windows 'installer' load from the USB drive and go into the disk partitioner. It will generate 3 partitions if you just let it go ahead. A small one, a hundred Mb as system reserved, a bigger one about 500 Mb as Recovery and the rest as C:\
The installer will format C: as NTFS and do what it does to the two small partitions. Then load the OS onto C: and get going.
If you are NOT doing a fresh install.
Plug the new SSD into a spare SATA socket ( or, if you have the cable, into a USB socket, and clone the current OS from C: onto it. Paragon make good free software to do this.
Then unplug the original C drive and plug in the SSD to that socket.
Boot the machine. Install the W10 USB drive and run setup from it.
After this you can install the old C drive ( which will now be a different drive letter into a spare SATA socket to retrieve any data.