Specifying Classes of Markov Chains

Alright. I am having a serious problem with this... we have 4 different probability matrices, but my question is in general.

We are told to specify the classes of markov chains, and determine whether they are transient or recurrent. I can tell whether or not the chains are transient or recurrent, but for the life of me, I can't seem to define the classes of them. If anyone can give me some tips on how to define these, that'd be great.

Here are the matrices, if you want to look at specific examples:

|| 0 .5 .5 ||
|| .5 0 .5 || = P1
|| .5 .5 0 ||

|| 0 0 0 1 ||
|| 0 0 0 1 ||
|| .5 .5 0 0 || = P2
|| 0 0 1 0 ||

There are others, but those are just 2 basic examples to maybe jog your memory.

Any help would be greatly appreciated.