So he sees someone interacting with some other tweet in a way he doesn't like, and then blocks them from following him? Having not used twitter, is this easy o

So he sees someone interacting with some other tweet in a way he doesn't like, and then blocks them from following him? Having not used twitter, is this easy one-click thing that takes no time nor thought, or is he having to switch screens and spend time on doing this? (Technically I became a twit yesterday because nitter stopped working and there is just one person's posts that I like to check up on, so I ended up giving in and logging in... :( But I still don't know the UI well enough to answer my own question :) )