Putnamto wrote:didnt know they acted like activated abilities, thought they would just let me tap them automatically just like a basic land.
so in order to spend that mana, instead of selecting the spell i want to play, then selecting the lands to tap, i would have to use/tap the nonbasic land, then play my spell?
The mana is confusing. Especially for new players until they figure it out. To briefly summarize lands that produce multiple colors of mana, like
Stomping Ground, cannot be correctly coded in the game. Therefore modders have come up with a few workarounds to approximate these cards.
- Manaual Mana tapping - This works just as Grovyle posted. To answer your question, to cast a spell with manual mana tapping you first have to use the activated ability to tell the land what color of mana to produce. This is added to your "mana pool". Once you have enough mana in your mana pool to cast your spell, you can cast it. On a note, your mana pool empties at the end of each step. So for instance you cannot tap a land during your Main Phase and then use it during your Combat Phase.
- Auto-tapping Dual/Multicolor Lands - These versions work just like basic lands like Islands with a minor exception. Like the manual mana you have to tell the card which color you want it to produce through an activated ability. Although instead of tapping and adding mana to your mana pool the card behaves like a basic land. It's easier to explain with an example so take Stomping Ground for instance. If you want Stomping Ground to produce
, you use the activated ability, select the
option and now Stomping Ground behaves just like a basic Mountain. If you want Stomping Ground to produce
just select the
option from the activated ability and it works just like a basic Forest.
I felt the need to elaborate on both types of mana cards because I know sumomole has both versions in his mod. I'm not sure which you are using but the easiest way to tell is if the land taps when you use the activated ability, it is a Manual Mana tapping land. If the land doesn't really do anything when you activate the ability it is an "Auto-tapping Dual/Multicolor Land". Judging by sumomole's response in his thread lands like
Stomping Ground and the other shock lands are the Auto-tapping, Option 2 described above. If you have any more questions feel free to ask

.
Edit - Also, I believe your mana pool empties every step not phase. So if add mana to your mana pool in the "Declare Attackers" step it will
not be available in the "Declare Blockers" step even though they are both in the combat phase. I guess it also empties after each phase but I consider this just a change in step as well but that may not be technically correct.