Now that you’ve chosen an army it’s time to learn the Warhammer 40K rules, so that you can in turn understand your army. Reading your army’s codex without a fundamental understanding of the game rules can be confusing.
I would also refrain from making any purchases for your army, except the codex/index, at this point as well. You want to make informed decisions when building up your army and spending money, so get a grasp on the rules, and your army’s rules before spending money.
Learning Warhammer 40K Rules
Once upon a time, the Warhammer 40K rules were long and complicated. Most versions of the game had rulebooks with around 100 pages of rules for the basic mechanics of the game. It was a lot to take in, and it took a lot of games before you became comfortable with the rules. Then 8th edition hit, and that all changed.
In 40K’s 8th edition, the core rules for the game are only 8 pages in length. Those core rules are also available for free. However, the free rules only contain the “basic” rules. It’s enough to get you playing the game, however, if you want the “advanced” rules as well then you will need to buy the rulebook.
The game of 40K has moved from a very restrictive ruleset to something more free than any edition prior. As such, learning the Warhammer 40K rules is pretty straight forward.
Where once 40K had various charts to determine rolls needed to hit something, wound it, etc., it has since adopted a much simpler method. It really is a simple game to learn, but it still has a deep level of strategy that’s expected out of a tabletop wargame.
There is no substitute for reading the Warhammer 40K rules. The biggest mistake I see players make is relying on a friend to teach them the game. The problem that occurs is that their friend may not have the best grasp on the rules, and in turn teaches the new player incorrect rules. Then because the new player isn’t reading the rules for him/herself, they never know.
I’ve seen this go on for years, and then when that player finally plays someone with a firm grasp on the rules there can be some rules debates, and that player’s only defense is that’s how they were taught.
Use your friends to help you understand rules, and clarify things, but not to teach the rules to you. There are no shortcuts here.
I recommend you try to tackle a section at a time. Read a section through then re-read it immediately after. It might not all make sense at the time, but as long as you’ve read it then when it comes up in your first few games you will at least recall seeing it.
Learn What You Need
As you’re going through the rules for Warhammer 40K the first time, I would consider skipping over anything that is not core rules, like Fighting a Battle, the types of game modes, Advanced Rules, etc. Eventually you’ll want to learn all of this. However, for getting started you really just want to concern yourself with the core concepts.
I wrote an article on how to play 40K faster. There are some good concepts in there that will help you out as you learn the game. Some of it has already been said in this article, but some of it hasn’t. If you learn those things early on then it will really help you out.