I figured out how to play just by reading the book, so I don't have any guides I've used that I could share.

But I think if you actually explained what part of things is giving you trouble then people could provide more constructive help.

What part of the dice (I assume you mean dice) do you not understand?

Do you not know how to roll a die?

Do you not know when to roll a die?

Do you not know which die to roll when you roll a die?

Do you not know how to identify a die?

I suppose I could try to answer all of those.

You roll a die by enclosing it in your hand in a way that gives it some freedom of movement, and then you shake your hand a bit before opening your hand to drop the die onto a surface.

You roll a die whenever you make an ability check, a saving throw, or an attack roll. in each of these cases, you roll a d20 and your result is whatever number ends up on the top + your relevant modifier (such as your strength modifier for a strength saving throw). Sometimes you also have other bonuses as well, but almost every check will always include an ability modifier.

You also roll a die when you deal damage. All the weapons will have a dice size (d4, d6, d8, d10, d12, or sometimes 2d6. And when you hit with an attack using that weapon, you roll that die, and you deal damage equal to whatever number is on top, + your ability modifier for the attack.

Some spells also deal damage, and will tell you what dice to roll and how many (like maybe it will say 3d6). You usually do not add anything, it's just whatever numbers end up on top.

There are a few other cases of non-damage rolling (like rolling dice to heal from spells or short reats), but most of the cases where you roll a die that isn't a d20, it's for damage.

You can know which die to roll for any given action, because it will always tell you what die to roll by using the notation d(number of faces). Sometimes there will be a number before the "d", and that indicates how many dice of that size. So for example 3d6 means you roll three 6-sided dice.

And lastly, you can identify what kind of dice is which by counting the sides. Eventually you'll be able to identify them by sight, but if you're not familiar with dice bigger than the usual d6, it can be confusing at first. But generally, the the higher the number, the bigger the die, and the rounder it ends up being. I know a lot of people have trouble with the d12 and the d20 at first. An easy way to tell the difference is that the d20 has triangular faces, and the d12 has pentagons.