I'd recommend a brand of pouches like others have. Obviously start with the lowest mg content. 3 mg Zyns are popular, relatively low dosed, and are considered "smooth". If you aren't used to nicotine the affects of it will likely be too much to leave in for a long time.
I use them when drinking, as I find it enhances the drunk feel which allows me to not have to drink nearly as much, and if I need energy at a point in the day that it is too late to have caffeine, as nicotine has a shorter half-life. I use them at work sometimes and don't really see any cognitive benefit aside from a calming affect.
Yes it's addictive. No, using it a few times a week sparingly will not get you addicted.