For your character to attempt to a skill, you would simply make a skill roll with a d20 and add your character's PB to the roll. if the skill roll is over the target number, the attempt was successful; if the roll is under the target the attempt failed. The target number is called the Difficulty Factor, or DF for short, and is usually 11, but can be modified by the Rac if the situation is more difficult or easier that normal. When attempting and skill, a Natural 20 is always successful and a Natural 1 always fails, regardless of the DF.
Modifying the Difficulty Factor
The standard number to beat the most attempts with the skill is 11, which is the Moderate DF. This is the base difficulty to use the most situations. If a more hazardous or inhibiting element plays a part in the otherwise normal situation the Rac will increase the DF to the High level. Should one or more hazardous or inhibiting elements play in at the same time, the Rac will increase the difficulty to its highest level, the Extreme level.
You must roll over or equal to the DF in order for your character to be successful. use the Difficulty Scale below to see the numbers that apply to each DF.
As always, a skill roll of Natural 1 is never successful, regardless of the bonuses, and results in a harmful or hindering consequence. This consequence is up to the Rac and will vary from situation to situation based on the skill your character attempted. Furthermore, any roll under 6 always fails, but no further consequences befall your character other than what results from failing the task. The Rac will use the simple DF when the attempt is very easy but your character still has a chance of failure. Sometimes, it may not be necessary to make a skill roll for the simple DF; simply having the skill is good enough. However, that decision is up to the Rac.
Many factors can increase the DF from Moderate to High, including the health condition of your character, the position your character is in while attempting the skill, or external elements, such as weather or hazardous surface conditions. Furthermore, the target of the action could be made in a way to prevent your character from tampering with it. For example, a locksmith deliberately makes a lock more difficult to pick by its mechanics, or positions it in a difficult place to get to, etc. Two more of the above factors imposed on a situation could increase the DF to Extreme, witch you may have noticed requires either a Natural 20 or many bonuses to achieve.
At any DF the minimum consequence for a failed roll is the loss of time and energy it takes to attempt to task. Characters with a low PAT will have to move on after failing a skill enough times. Furthermore, your character could be putting the party in some kind of jeopardy by spending too much time on a skill attempt, considering the height the DF the more time and energy it takes to accomplish the skill.