There are three parameters that gauge how much Mars has been terraformed: temperature, oxygen, and oceans. You and your fellow players are competing to contribute the most to the terraforming of Mars. Each of these symbols indicates raising the associated parameter one time. Each time you raise one of these parameters, you will gain 1 TR. Every aspect of preparing our new home is equally important. Only when our atmosphere and ocean levels are perfectly maintained can we begin to bring over our citizens.
Raise the temperature by 2˚C. Heat, MC, or effects on cards can be used to increase the temperature. The temperature starts at -30˚C and can be raised 2˚C at a time up to +8˚C. This will create an equatorial zone where water stays liquid.
Raise the oxygen by 1%. Plants, MC, or effects on cards can be used to raise the oxygen level. The oxygen starts at 0% and can be raised 1% at a time up to 14%. At 14% the atmosphere resembles that of Earth at a 3000m elevation.
Flip one ocean tile. MC or effects on cards can be used to flip ocean tiles. Each ocean tile represents 1% ocean coverage. The ocean coverage starts at 0% and can be raised 1% at a time to 9% (or, 9 ocean tiles). With 9% of the surface covered by oceans, Mars will have a hydrological cycle, creating rain and rivers.