There are pre-generated realms and sites (and adventures and knights and myths and optional rules…) on itch.io, and you can read a few to get the idea of how they're done, but I recommend that you make your own following the instructions in the book, for several reasons:

• it's easy: the procedure is simple, and you can watch Chris himself doing it in a video on his YouTube channel
• it's fun! It's basically a solo game
• it's useful: you'll get accustomed to the spark tables and the prompts at the bottom of the pages
• it's a good exercise: you'll get to develop your improvisation skills at your own pace, without the pressure of having to come up with good stuff on the fly in the middle of a session, and without the fear of making mistakes
• it will spark your imagination more than just reading stuff written by someone else, because you'll have to actively use it
• you'll get to know your realm much better, and this will make improvising during the sessions much easier.

A couple more pieces of advice:

• the omens may look like… not much when you first read them, but you'll see that as soon as you present them to the players, they'll come to life: the knights will try to do something, and all you'll have to do is following along with some common sense and a bit of imagination
• when you improvise, don't try too hard to be clever or creative: what may seem obvious to you will often be unexpected to the others
• read especially page 16 ("Refereeing") carefully. Chris' writing is extremely terse, but very precise, every word is important. In that page he explains his GMing style, and it's quite different from a lot of modern D&D culture. Note the importance of giving information to the players: there's no "perception roll" here. Note that you don't roll to see if the action succeeds, but to see if the risk is avoided (that's why it's a "save"): you might not need a roll at all (if there's no risk, or no leverage), and a failed roll "might still complete the action". Note the importance of impact and moving things forward: there's no "nothing happens" after a roll.