Skills have five ranks from untrained 0 to master 4. Some skills cannot be used untrained, they are marked with *.
Skill levels 1 and 2 cost points equal to skill level, 3rd skill level costs additional 2 points (4 points total). 4th skill level costs 8 points.
Skill lists are given in different settings. You can add skills if you feel like it. Another method is to take excisting roleplaying game and take skill list from it.
It is your choice do you want skills to be extra specific or more wide. Generally in YDIN skills are in wider area but there are few of more specific also.
Some skills have subcategories. You can use subcatogories with the main skill in one negative modifier, or buy them separately as you choose to ignore the negative modifier. Skill's subcategories are marked with a +.
When attempting a skill task, skill is always paired with an attribute. Attribute might vary depending on a situation though. Skills aren't linked specifically on one attribute, but some skills usually use one particular attribute.
Hobbies are treated like general skills.