This is a test of commonsense. Complete the next sentence:

How to use your samsung galaxy tab as a phone
Check for sim card support.
Galaxy tablets have two versions: one that supports a sim card and one that doesn't. Refer to the tablet's user manual to see whether the android device you have supports the said feature or not.
You can also look around the sides of the tablet or behind its battery for any slot that a sim card might fit in. It's a small slot only a little larger than that of a memory card, and is very easy to find.