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They might also be called proficiencies. Are they just the modifier of the appropriate skill or something else?
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Each skill says which attribute is used in the parentheses on the right side. For example the Skill Deception uses Cha. Cha means Charisma. This means that you just use your Charisma modifier. If you are proficient with a skill you also add your proficiency modifier, which is +2 at level 1. Your character has a Charisma modifier of +2 and a proficiency bonus of +2. So you just write +4 at Deception. You do this for all skills and add this bonus or malus to every roll where your DM says you are using this specific skill.
Str = Strength
Dex = Dexterity
Con = Constitution
Int = Intelligence
Wis = Wisdom
Cha = Charisma