Hi Tempest, and welcome! You say "you know nothing about computers".... yet, you have used one to get here and to begin asking questions. But I'll accept the idea that perhaps you know "little" about computers and that instructing you will take a lot of time. We are all volunteers here, and none of us have the time to be a full-time tutor to you. But there are many people here who will jump in and help advise you as we go along.
On your next reply, please tell us what kind of computer you are using. Is it a desktop, or a laptop? What brand is it (Dell, HP, Acer, etc)? Do you know what "model number" it is? If you can tell us those things, we may can look it up online to find out more details that we may need to know (like how much memory it has). Do you know if you are using Windows 10, or Windows 8, or Windows 7..... or are you using a Mac computer?
If I were to attempt to teach technology to a 5-year old, as you suggest, I think that some of the first lessons would have to be vocabulary. I'm sorry, but you have to learn new words and terminology to understand the complexities of installing and using a new computer operating system (and that is exactly what Linux is). If you don't have the patience for this, you should give up now and save us all a lot of time and effort. It will help if you are ambitious enough to Google for words you don't understand, but you can stop us and ask to try to explain things better for you. We may Google for answers ourselves and just give you a link so that you can go read up about something in question... a word, or a computer device, or how to perform some task.
So, with vocabulary... I've already used just a bit above. Any questions? Or how about these terms: mouse, keyboard, monitor, DVD-ROM, USB flash drive? And a few more before I stop for tonight... how about: RAM, BIOS, UEFI, hard drive, partitions, format, boot (warm boot or cold boot), file systems (such as FAT32 or NTFS). Okay, that's enough for now. Either you know some/all of these terms, or else maybe your head is swimming already. But you will need to learn and understand most of these words if you hope to download and install Linux.
Sometimes a better solution is to take a local class where you live and get some computer basics down first. Another possibility is to find someone local to you that will be a personal tutor to help you. There are thousands of YouTube videos that can teach you things also, especially as you learn the language so that you know how to search better. There are many different versions of Linux, so as you search you may want to just concentrate on one or two... some suggestions are Linux Mint and Ubuntu. These are often the most user-friendly for new people just getting started, but there are many more that you may want to consider in time.
Cheers