Well it'd be best to sign up to Aeria as a first, as joymax sucks.
You start of the world by creating a player form 3 choices, after this you pick your starting digimon. (You can get more eggs as you play the game, and complete quests.)
As you start their is a tutorial to teach you the basics, after it's pretty much do quests or just a free-roam f2p world and do as you please. Wether it be party with friends, chat, hang around the market area or to try and kill other digimon to gain more parts for eggs to hatch new more powerful digimon.
The more you level the more area's and digimon and quests you can take on, it's very challenging as you progress but also fun! You can also enchance your digimon's power using clone's, and have your own personal names for each of your digimon. You are a player and your digimon will follow you everywhere, but when you go into battle your digimon does it and you command it by the action tool bar at the bottom and can choose when you want them to digivole
. It's sweet, and can't really think of more to say atm aha but do recommend trying it.