How to Buy a Lore
Lores are bought with Focus, rather than being bought with RPG points. Every lore level costs a certain amount of Focus to learn. This is equal to the lore's cost multiplier (normally 1, but it may be as much as 5), times the level of the lore. So, for instance, if the cost multiplier is 2 and you are learning level 5, it will cost you 10 Focus to buy.
To increase your level in a lore (or buy the first level in it, if you don't have it yet), use:
This will automatically spend the necessary amount of Focus.
If you don't have enough Focus to buy the lore right now, or you just want to spend Focus a little at a time, you can use:
+lore/learn lore-alias spending amount
This will let you "bank" points towards learning the lore. +lore/learn shows you what you're currently learning.
Before you can spend Focus on learning a lore, you must meet its pre-requisites. In most cases, there is more than a single path to learning a lore, and in most such cases, at least one of the paths will involve training. Broadly speaking, this tends to mean that either someone can teach you about it directly, or you can go learn a broader set of lores that allow you to self-discover this next level of lore.
Note that training does not replace the Focus cost of learning a lore. The Focus expended by a trainer is Focus that goes towards meeting the training pre-requisite, and not your cost of the lore. You still have to pay the full cost of learning the lore, regardless of whether or not you've been trained in it. Your Focus cost represents the time and effort that you're putting into your learning; your trainer's Focus cost represents the time and effort he's put into your training.
Lore Learning Times
While you can buy lores at 1 and 2 as quickly as you want (although you should still make sure that these purchases make sense IC for your character), raising lores to 3 and above potentially involve a time delay.
Every lore has a type; it's the first two letters of the lore alias, i.e., the type of the "AL-Amber" lore is "AL". The more lores that you have of a given type that are 3+, the more of a time delay is enforced for raising other lores of that type to 3 or higher. This delay does not affect people who don't already have high lores in a category.
This is essentially an anti-abuse measure. It's intended to prevent experienced characters who have already established themselves in several fields of expertise, from going from knowing nothing about something, to being a reknowned expert in it, in less than a month. Because it scales with the number of high lores that you already have, it doesn't impact new characters who are trying to raise their initial lores to establish their areas of expertise.