Windows users should download Slackware ARM via FTP from ftp://ftp.arm.slackware.com/slackwarearm/ or any of the mirrors provided on the Slackware ARM: Get Slack page (at the bottom). Use BINARY mode to download the files and not ASCII! Once downloaded, transfer all the Slackware ARM files (retaining their original directory structure) onto the root of your USB memory stick. If not in the root, a directory where you will remember the location.
Linux users have the option to download Slackware ARM Linux from ftp://ftp.arm.slackware.com/slackwarearm/ (use BINARY mode to download the files and not ASCII!) or by a much easier and simpler way of downloading Slackware ARM, using 'rsync'.