If you are sure that your tablet is 3G, then it has the ability to be used together with a GSM SIM card. To be noticed that you probably won't be able to make or receive calls on your device. The SIM can be used only to connect to the Internet using a 3G network. For additional information in this matter, I strongly suggest to head over to the manufacturer's official website. There, after you searched for your device, you should be able to download any additional applications or an user manual which will explain the steps that you need to follow to be able to use the GSM SIM card.