To download updates for your Samsung TV, go to Samsung.com, click on the Owners & Support tab, and then click on the Manuals & Downloads link. Once on this page, type your TV's model number or name into the provided search box to find downloads for it.
Once you've downloaded the appropriate firmware update for your TV, determine how to transfer it to the TV for installation. The easiest way to do this is to unzip the compressed file, and then copy the resulting folder to a USB flash drive. Once you have the folder on a USB drive, you can plug the USB drive into your TV, and use the menu to install the firmware update.