1. Use a browser to navigate to the SME website
https://forums.contribs.org/2. Click on the "Download" on the top menu (black line, white text)
3. Select "SME Server ISOs" and click.
4. Select the ISO version you want and click on it. (i386 for 32bit PC and x86_64 for 64bitpc)
5. Search online for CDburnerXP (my favourite but there are many).
6. Install CDburnerXP (or whatever burner programyou choose instead).
7. Use the burner program to burn you ISO file to DVD. Make sure you BURN it and not COPY it.
Good luck.
Ian