1 put in the USB flash drive
2 wait for windows to recognise it and install the built in windows drivers to run it
3 find the files you want to transfer highlight, press ctrl c (or right click, copy) and then on then type in the drive letter of the USB drive and press ctrl+v (or right click and paste)
you can leave the window/folder of the USB drive open and drag over the files whilst holding CTRL and it will copy them over.
dont delete them off of your computer, should something happen to the USB drive they will all be gone.
since there word documents, they compress really well. download something like winrar and compress them for backup, or compress them and save them onto the USB drive.
they will take up a fraction of the 4GB.