The Lore skill is about knowledge and education. It covers all areas of Scholarship and Academics. It requires the character to have an existing area of study compatible with the information desired.
Overcome: You can use Lore to overcome any obstacle that requires applying your character’s knowledge to achieve a goal. For example, you might roll Lore to decipher some ancient language on a tomb wall, under the presumption that your character might have researched it at some point. Frankly, you can use Lore as a go-to skill any time you need to know if your character can answer a difficult question, where some tension exists in not knowing the answer. However, this can only apply if your character's area of study could reasonably be expected to contain a useful answer (a Druid doesn't know anything about Machinery).
Create an Advantage: Like Investigate, Lore provides a lot of very flexible opportunities to create advantages, provided you can research the subject in question. More often than not, you’ll be using Lore to get a story detail, some obscure bit of information that you uncover or know already, but if that information gives you an edge in a future scene, it might take the form of an aspect. Likewise, you can use Lore to create advantages based on any subject matter your character might have studied, which gives you a fun way to add details to the setting.
Attack: Lore isn’t used in conflicts.
Defend: Lore isn’t used to defend.