I work at Target (cashier) and there is this hb8 that works at the pizza hut inside the store.
I've been wanting to game for a while now but I have no idea how to approach. whenever we make eye contact she smiles. I'm not sure to take that as a IOI or just friendliness.
any ideas on how to open in this kind of situation?

This one should be fairly easy! As an example, on your lunch or whatever, go get a slice of pizza. As an ice breaker, next time she smiles at you you could say something like "So is smiling a part of your job description or do you just like smiling at me?" - play it off as a joke, but it should evoke a response anyway. Always try to prepare for whatever outcome:

- "Yeah it is"
-- Act hurt from here, something like "Aww, and there was me thinking I was special".
-- "So everyone gets that smile and not just me? Damn!"

- "Not everyone/not a part of job description"
-- You've just broke the ice and got an IOI. Follow up with a chat routine, flow into your mid game. Ask her if she goes out often/where she goes, does she fancy going out sometime. I'm somewhat new to the game - depending on your approach you may not want to seem TOO eager, but I've always found a bit of interest doesn't hurt either. Try to avoid getting dropped into the friend zone though, as it's always hard to break out.

I'd wait for a few more responses, as I said I'm fairly new to the game and some of the PUA's here might say my advice is wrong!