I managed to sneak into the 3.2 ptr to check it out. This is how the new totem bar works:
First of all, you have to learn 3 new spells from the Shaman Trainer. Those spells are Call of Air, Call of Fire and Call of Water. Each different Element represents a different combination of totems you can set, when you use the specific spell.The totem bar is situated above your bottom left action bars and it looks like this:
The first icon is the "Call of ..." spell you have set in the bars. Since there are 3 different "Call of ..." spells, you can have up to 3 different combinations of totems saved in your totem bar.
The second, third and forth icons are the Earth, Fire and Water totems set in combination in each respective slot.
the last totem on the right (the darken one) is called Call of Earth and it removes all the totems set giving you 25% of the mana used to set them altogether (yeah, its Totemic Call).
if u mouse over one of your totems, a little arrow appears above it. By presing the arrow, all the totems of the specific type(element) appear. Here is a pic, showing the extensions of each totem pressed.
In order to remove a specific totem from a combination (so that you can set for example 3 totems together each time), just drag the icon of the totem by holding left-click and simply remove the icon from the bar.
You can also just click on a totem on the bar to set it down, without having to set all 4 totems together. As a result, there is no need to have all you totems on your action bars anymore.