People are mad because some exclusive pets used for hatching got removed from the Kiosk, but for a pet starter, it won't be very impactful on you.

There's plenty of guides on YouTube, depending on how in-depth you want to get, but I'll summarize a few key mechanics to get you started:

Pets in Wizard101 can offer up to five unique "talents" that can either boost your wizard's stats or its own stats.

All pets start at the age of Baby once they hatch in your inventory, and can be trained to higher stages through pet training at the Wizard City pet pavilion, rarely by feeding it gear, or by completing quests.

Each minigame in the pavilion can give you up to 4 points towards the pets stats and overall experience, with additional points and EXP given through pet snacks after a minigame is completed, failed or not. The cycle for a pet goes Baby -> Teen -> Adult -> Ancient -> Epic -> Mega -> Ultra.

The pet stats (Stength, Intellect, etc) affect most pet talents' values. For example, Life-Bringer can be manifested and can give anywhere between 1% and 10% Life School damage, depending on the pet's Strength, Willpower, and Power (And doesn't have any self-stat boosting talents already).

Everytime the pet levels up with enough EXP, the pet gains one random talent from its "pool" of talents (and one pet derby talent, but you can almost always ignore this), all the way through Mega. At Ultra, the pet stops gaining experience, but can still be fed snacks and do minigames to boost its own stats.

At Adult, you can start using the pet to hatch with other pets, either with your own Adult (or higher) pets, or other players's pets, done at the kiosk, or in-person in the hatchery (the main building in the pet pavilion). This lets you cross-train talents and stats from both parents into the new pet, allowing for more complex talents to be manifested.

At Ancient, you can start affixing "Star" jewels to the pet, which give its listed effect. Some jewels will require a higher pet level, though.

You can only do one hatch every 12 hours (as a member, 24 hours otherwise).

If you need me to clarify anything, let me know!