You can try completing certain quests or participating in specific events related to it. Sometimes, rare drops from monsters might also give you a chance to obtain it.
One good order could be starting with the Tutorial Island quests as they introduce the basic mechanics. Then move on to the Lumbridge quests which are relatively easy and build a foundation. After that, quests like the Vampire Slayer quest can be a good next step as it has an interesting story and unlocks some useful items and areas.
For a new player, start with the basic beginner quests like the Imp Catcher. It's easy and gives a feel for how quests work. Then, try the Witch's Potion quest which is also simple but starts to introduce more of the game's world. After that, the Dragon Slayer quest is a big step, but it has a great story and is a classic in the OSRS quest line.
Ruby could be anyone. It might be a name given to a character in a specific story or just a name of a person in real life who likes to read stories in her own time.
Well, her sister Yang would definitely be one of the main characters. Yang would be very protective of Ruby and would try to help her in any way she could. Weiss would also be important. She might use her intelligence and Dust - related skills to assist Ruby. And Blake, with her stealth and combat skills, could be crucial in protecting Ruby and guiding her through difficult situations.
I don't know exactly who Ruby is without reading the story. But she is likely the main character, a person who has some kind of story related to reading in the street during her own time.
The relationship between Max and Ruby makes it special. Ruby's caring yet sometimes bossy nature towards Max creates an interesting dynamic. It's a story that many siblings can relate to.