Short answer: you don’t.

Long answer: there’s no flair system in the Threadiverse (Lemmy + Kbin). We are working on building one limited to our instance but that takes time. Even then, once it will be finished it will only cover our instance. Users from other instances or platforms (such as yourself) will need extensions and 3rd party tools to get access to them. I plan on building those as well, but it will be only after the flairs are fully functional for our local users who of course are our primary concern.