I am implementing a radio button group and I was wondering about the instructions here
https://www.w3.org/TR/wai-aria-practices-1.1/#radiobutton

Specfiically this bit:

Space selects the radio button with focus and de-selects other radio buttons in the group.

Slightly before that, it says that left/right/up/down keys should cycle through the options of a radio group by focusing and selecting them. Can you explain how it is possible to focus a radio option without selecting it, such that the space key would then be necessary to select it?

I hope this is the right place to raise a question like this, please let me know if you know of a better place, thank you!