I'm not sure this is in the right forum? Maybe it is though.
Anyway - devotion is the total number of a particular mana symbol that you have in permanents under your control. That doesn't count the colourless mana numbers - only mana symbols. It is not quite the same as the cmc.
Mogis's Marauder adds one black devotion, not 3.
Fanatic of Mogis adds one red devotion, not 4.
I literally just answered a question about this for you. Please just ask for clarification instead of posting another question.
As I just defined for you here, devotion is the sum of all of a color's mana symbols in the mana costs of permanents you control. Devotion only counts mana symbols in mana costs. It doesn't count colored permanents or anything else.
For example, Precinct Captain counts for two devotion to white. The tokens it creates don't count toward devotion because they don't have mana costs.
is the spell you are casting plus what permanents are already are on the battle feild?
Spells have nothing to do with devotion. Again, devotion counts only mana symbols in the mana costs of permanents you control. Spells are not permanents. Spells only exist on the stack, and permanents only exist on the battlefield.