What was wrong with your old thread?
An iso is an image of a CD (iso9660 format).
You need a CD and a CD-burner that can burn the iso *as a bootable image* - not burn it as a plain file.
Make sure your computer can boot from a CD (may need to twiddle the BIOS) - put the CD, boot, read the message, use fdisk, run setup, follow the steps.
There are a lot of threads on this, especially in the Slack forum. Search LQ. Also, as I said in the other thread, the book at the Slack site will answer a lot of your questions. It's a little out of date but mostly valid.