Ubuntu – How to install PYPY3 on Ubuntu, for newbies

I want to install pypy3 in Ubuntu. I have read the answer for this question "How to install PyPy3 (2.1, beta) on Ubuntu?" and still have no idea what to do. Could some kind soul please explain it so that even I can understand it 🙂

Here's what I have done so far:

Went here

Read that I had to go here

Downloaded: pypy3-2.1-beta-linux_x86_64-portable.tar.bz2

Opened it with the Archive manager (because it seemed like a reasonable thing to do)

Extracted it to desktop/PYPY3

Then desperately tried all the shell commands I came across last night. I will not be able to give a clear account of what I tried and what errors came back, as it is kind of a blur to me at this point.

But I can tell you that I got the Tar thing unpacked at one point and that I have tried running the pypy executable from the command line from the folder containing it, but got this:

bash: /usr/bin/pypy: No such file or directory

Could someone please tell me what to do. (have read the readme, the install docs at pypy.org and lots of posts)