[quote=@vancexentan]
Well infernoids aren't my cup of tea as it is. I'm asking on how I'm supposed to specifically use the monsters. Can I only special more than one from the hand and then am limited to one monster when using the grave?
[/quote]

You're limited by the level on your field. So long as the total level of monsters on your field is 8 or lower, you can summon as many infernods as you wish so long as you can pay the cost. Inferoids levels 1-4 can only be summoned from the hand, the rest can be summoned from the hand or graveyard.