You put them in your mouth and you swallow them.

Cold water extractions will help isolate the codeine from the acetaminophen. The process involves crushing the tablets, soaking in a little cold water and drinking the liquid. Complete guide found here: http://www.poppies.org/news/96924960077672.shtml

This doesn't seem very necessary to me though, since Tylenol 3's contain only 300mg of acetaminophen and even taking even over 5 of them wouldn't add up to a high enough dose of acetaminophen to result in any danger. (Unless you've already exceded 3000mg that day.) It is more for pills containing a lower dosage of codeine. The 3's have 30mg.