IDR installation help

I am seeking installation assistance. I have tried twice to install IDR.

I first tried python 3 setup.py. install as instructed in the manual.
I received the following error:

[Errno 2] No such file or directory: ‘Library/Python/3.8/site-packages/test-easy-install-53208.write-test’
The installation directory you specified (via –install-dir, –prefix, or the disutils default setting was:
/Library/Python/3.8/site-packages/
This directory does not currently exist. Please create it and try again, or choose a different installation directory (using the -d or –install-dir option)

Following I realized my python site-packages are in my home directory . /User/myhomedir/Library/Python/3.8/lib/python/site-packages

I added this to my python path and attempted the install again.
This time specifying the prefix python3 setup.py install –prefix=/User/myhomedir/Library/Python/3.8/lib/python/site-packages .

The install was again unsuccessful and I got this error

You are attempting to install a package to a directory that is not on PYTHONPATH and which Python does not read “.pth” files from. THe installation directory you specified (via –install-dir, –prefix or the distutils defuault setting) was:
/Users/myhomedir/Library/Python/3.8/lib/python/site-packages/lib/python3.8/site-packages/
and your PYTHONPATH environment variable currently contains:
‘:/Users/myhomedir/Library/Python/3.8/lib/python/site-packages’

Could you provide any assistance/ provide explanation.