Asking Alexa to add the Radio Skill is the easiest way to get it working, failling that, there are 2 ways to enable the skill, whether you are using the desktop on a MAC/PC or on your phone.
On your desktop, go to your main Amazon page, at the top of the page is the search bar at the left hand side it says all. Click on the 'ALL' to get a drop down menu, select Alexa skills then in the search bar type Radio Ship and press enter.
Click on the skill when it appears and then click the "enable skill" option at the right hand side......well done now all the Alexa devices you have are now able to receive The Radio Ship.....go on try them.
This can also be done with your smartphone, go to your local Amazon site type in "alexa skills The Radio Ship" then search, the results will start with some Alexa offers and then below them will be the skill you require, with it's famous Red Radio Ship symbol open it as above and click "enable skill" once again well done.
Alternatively open your existing Alexa app click on the "more" option, select "skills & games" next tap on the magnifying glass at the top to bring up the search field. Type in “Radio Ship”, you know the drill by now....tap on the "enable skill" button and it's added to all your linked devices.
Whichever way you do it, once the Radio Ship skill is enabled, all you need to do is say “Alexa play The Radio Ship” to your device and it will start playing the stream......happy listening, and don't forget to tell your friends, or even better show them and enable The Radio Ship for them.