If you grab a goblin for example, and the goblin test to escape it says to have it make an acrobatics or athletics check but I can't seem to find where it says there skills? Any help?
Creatures' skills are listed at the bottom of their info sheet/card.
Creature sheets have ability modifier + half level, which is what you should be using, already calculated at the bottom of the sheet.
For example, a level 14 lich necromancer has the following ability stats at the bottom of his/her monster sheet:
First the skills the lich is trained in are listed: arcana, history, and insight. Their modifiers are listed as well.
All other skills are just half the creature's level plus the appropriate ability modifier, which is already calculated for you. If you wanted to know the lich's athletics modifier, you would look up athletics in the PHB, see that it's based on strength, and use the listed strength modifier (+7). If you wanted to know the lich's acrobatics modifier, you would look up acrobatics in the PHB, see that it's based on dexterity, and use the lich's dexterity modifier (+8).
Exception: Perception is not listed with the other skills; it's up at the top next to vision types (darkvision, blindsight, etc). (Thanks Glen!)