get_iplayer installation guides
COMPREHENSIVE GUIDES TO GET YOU STARTED QUICKLY
macOS Quick Install Guide
Option 1 - Get iPlayer Automator (Very easy)
There are a couple of options on Mac. The easiest of the two is to use Get iPlayer Automator, a free tool that greatly simplifies the process of downloading content from the BBC (and now ITV) and have it deposited straight into iTunes.
Most Mac users enjoy this 'just works' setup and are not interested in the details underlying the programme. If you fit this description you can download Get iPlayer Automator or find out more on the Get iPlayer Automator site.
I have not used Get iPlayer Automator, so I can't help you with it, but you can visit the Get iPlayer Automator issue tracker if you get stuck.
Option 2 - Homebrew (easy)
Homebrew is a package management solution for macOS. It's very easy to install, just go to the Homebrew website and copy and paste the one line installation code into your terminal window.
Once you've installed Homebrew, it's just a one more line to get get_iplayer installed:
brew install dinkypumpkin/get_iplayer/get_iplayer
Upgrade to future releases with:
brew update brew upgrade get_iplayer
Get started by reading the guides and release notes
There is loads of info in the guides section to get you downloading programmes in a snap. Make sure you read the whole guide to understand what's happening and why you need to do things a certain way.
Find the release notes in the wiki. Read at least the notes for the latest release. Things can change quite a lot between releases and you'll find explanations there as to why get_iplayer is working the way it is.
You can take a look at the macOS installation page in the wiki for a bit more info and for instructions on performing a manual installation.