PSN Question

I'm not a PlayStation player, I know nothing about how to secure a PSN. To the point, can someone show me a tutorial or tell me how to secure a PSN after it is bought. The reason for this is I'm thinking of playing PS3 more often on my sisters PS3 and I rarely play Xbox now since most of my friends are on the One and I'll be getting the One in a later date. It would be nice if someone could educate me about the PSN, how to secure, how to not get pulled back (if that's possible), etc.. I'm contemplating buying an OG to use while I'm on PS until I get a One.
Thanks

I know a guy who sells them from a device other than ps3 so if you were to buy one all you would have to do is change the password and you're good he's a nice guy he currently has the account "Control" that's how I reach him

Make sure you get at least the Date of birth an og email to the PSN you buy. Not all of them come with the serial to the console it was created but that is always nice to. Anyone saying otherwise is lying or is just plain retarded trying to make a quick buck. Also deactivate all ps3s off the account once you buy one. If you are looking for a safe PSN to buy hmu, I have a nice one