All actions are performed using a percentile die roll. Actions are either General or Specific, as defined by the GM. Combat related rolls are always Specific, and you should read the rules section about combat to better understand the details.
In some cases your GM will tell you that either a specific skill or attribute roll is needed to perform an action. All Skills, as previously covered, have linkage to an attribute. When performing a Skill roll you take the rank of the skill, add the rank of the linked attribute and then multiply the total by 5. This gives you the percentage target that you are rolling for on your dice.
In the case of a General roll you simply must roll that target number or less to succeed. No specific additional detail is needed.
Note that the GM may, before you roll, assign penalties to your actual chance of success, due to environmental or personal situations (such as injuries).
For a Specific roll the GM wants to know more than success or failure, but the degree of success if you succeed. In such a situation you must state the difference between your percentage target and the actual roll you made (that is, subtract your successful roll from your percentage target and state to the GM what it is).
The GM then takes this result and compares it to the 3rd column on the Action Table Array (the one labeled specifically for skills) to determine what kind of success you achieved.
A limited success is one that has worked, but may have some drawbacks or problems. For example if picking a lock you may have opened it, but damaged your pick beyond usage, or made an excessive amount of noise. If cooking you might have made edible but not great tasting food, or burnt part of it, or injured yourself in the process of preparing it.
A moderate success is an average one. You did what was needed and without major additional problems, but it's not the best that could have been done or anything fancy.
High, Exceptional and Colossal successes are degrees of excellence, important if dealing with entering contests or creating items of quality (such as artwork). The GM may reward special benefits in some cases, such as improved results or reactions above what was expected from others upon your efforts.