It does matter which one you make a pact with. Infact, it's usually customary to know who you are trying to summon.
None of the rituals are easy. They are difficult, drawn out and can cause some pain especially if you've never done it before. If you do it wrong, odds are you are not going to get the entity you hoped for and will either get nothing, or whatever entity decides to take advantage of the situation. Infact, usually you would get this sort of deal from a demon as a diety isn't going to even bother with someone who is unwilling to worship them or plans to use and discard.
I wont give you a "risk" lecture, but the fact that you want a "good and easy ritual" tells me you are in no way ready to disturb any being and try to barter with them.