I do agree ^
League is super complex, and I promise you that it will take you a while to get a full grasp of it.
Runes are additional base and scaling stats that you can customize and take into each match. The link that Angry Monster gave is great for all of the information on Runes, but I would also recommend using this link
http://leagueoflegends.wikia.com/wiki/List_of_runes
The most important thing to take note of when it comes to runes is which rune type is Primary for it's set.
You can absolutely get AD Marks, Seals, Glyphs, and Quintessences, but you will actually get the most value from the Marks and Quints only, because they are primary. You are better off getting Seals and Glyphs of their respective primary sets.
Two pages I would honestly recommend getting
AD Page
- Attack Damage Marks
- Armor Seals
- Magic Resist Glyphs
- Movement Speed Quintessences
AP Page
- Magic Penetration Marks
- Mana Regeneration Seals
- Ability Power Glyphs
- Ability Power Quintessences
There are options of Tier 1, 2, and 3 runes. If you just want to have runes, you might want to grab Tier 1 or 2 sets, but remember that you can not resell them. After you get your Tier 3 sets, the Tier 1 and 2 sets are useless. Kinda sucks, but just letting you know.
All of these, except for movement speed, have flat and scaling options. It is really up to you which you pick. Flat will of course give you more of the stat at the start of the game, but scaling will give you more at the end of the game, usually out scaling flat runes by level 6-8. Personally, I would go for the scaling options, but sometimes it is nice to have that added power in the beginning of the game so you can be more of a bully and start snowballing. With scaling stats, you often need to play a bit more safe early on.
One last thing I would add, .. It may not be practical for starting out because they are so expensive, but I personally recommend getting Hybrid Penetration Marks instead of Magic Penetration Marks on your AP Page. All AP champions still need to be able to deal physical damage, and most of the time they don't deal much of it, so getting the hybrid penetration will often be more helpful in the early game, while still helping with your magic penetration later game, but not as much. So again, it's completely up to you.
Overall, experiment with your own ideas, and have fun.
[slayer-jinx-wink]