1. Click on an item that can hold charms to open the item up - drag and drop the charm onto the hole in the item. Note - charms can NOT be removed once inserted - the process is irreverseable - so choose wisely.
2. Buying a skill means you now know enough to assign points to that skill if you have earned skill points by leveling-up. You do not HAVE the skill you merely have the ability to LEARN the skill.