Advance the APN of "three" in the "Settings / ..." type into the tablet; Infect stick and waiting for something -> appears after some time in the Android status bar (screen upper edge - right) the already known from mobile phones forth antenna symbol with the various bars that indicate the reception strength ... and surfing is possible.
Furthermore, in principle: if one is used, the liquid working with a notebook, then you have to rethink of these tablets with Android some - because just everything takes a little longer and tougher runs somehow from .... was getting used to for me as Android newbie .. .. the tablet is just not a notebook replacement, special a supplement. The advantage is the ease of transportation ...
This statement is quite the good usability of this Tablets (I'll mainly use to gather information or queries from WEB-emails) do not diminish - but it is quite suitable.
To be clarified question would possibly, at what expense the internal battery is replaceable (or not) or whether and how to refer an original replacement power supply.