Sprint → Mobile broadband question?

okay, lately I've purchased a lenovo V570 laptop, and under the battery pack, there is a SIM card slot. I would like to know how this works, because all ive picked up so far is that you can buy a plan from a cell service, like sprint, and then stick a SIM card in the slot and you'll have mobile broadband. could someone give me the details, and tell me the best choice?

You would need to check with lenovo to see who the built in WAN modem is compatible with.

Sprint is a CDMA provider, there is no SIM card involved in CDMA systems, they use serial numbers assigned to each device instead of a SIM card.

You could always get a Sprint USB device to connect to your laptop's USB port.

I thought the ideapad series supports wimax? My friend has the same model and uses Clear.
Edit: His is an older model and they still use the same model numbers.