Beginner Tips

Hi all! I want to get Sea Monkeys, but want to be prepared before I start. I just read the Wiki and it seems like there are many things I could buy, but I'm wondering what else besides the kit is necessary? Also, what is the best kit?

For context, I live in a colder climate (especially if I keep them on a windowsill), and I've never had a pet before so I'm really anxious about doing everything right so they don't die...

Any tips would be appreciated!