Installing Keyboard
 

Which of these keyboards should I install for learning Spanish? I don't know the differences between all these.

Install the Spanish (United States) one. My second choice would be the Spanish (Latin America) one.
There's not much difference between the Latin America keyboard and the others (except the one for Spain), as far as I know.

I installed it, the problem is, that the accents are always going the wrong way. What does that mean?

ù instead of ú.

You aren't pressing the right key combination.

I think I got it working now. What does that other symbol mean?

@Genesis: The "grave accent" (`) is not used in Spanish, but in other languages, it indicates how a vowel should be pronounced. (In French, for example, "è" is a more open and long sound than "é".)

In Spanish we only use the "acute accent" (´), and it marks what syllable should be stressed in the word.
It's important to use it, because a change of accent may imply a change of meaning. For example: "Término" (end, conclusion) is not the same as "termino" (I finish) or "terminó" (he/she finished).

You said that you installed the Spanish-United States keyboard.

You can type the accented letters áéíóú and ÁÉÍÓÚ by first typing ' (apostrophe), then typing the letter. Similarly, you can type ñ and Ñ by first typing ~ (tilde), then typing the letter. If you want to type ' by itself, you have to type ' once, then press the space bar.

You can also type all of these accented letters by pressing and holding GR (which corresponds to the ALT key on the right side of SPACE) while you type the letter.

Sometimes you need to type ü or Ü. There are two ways to type it. First, you can press " (quotation mark) followed by u or U. Second you can type GR + y for ü or GR + Y for Ü. If you want to type " by itself, you have to type " once, then press the space bar.

Most of the special punctuation marks are accessible by pressing and holding GR while you press the usual key for a similar punctuation mark. To find all of them, you may want to press and hold GR while you type all of the number keys and punctuation keys on your keyboard. When I do that on my keyboard, here's what I find:

¡ = GR + 1 (opening exclamation point)
² = GR + 2 (superscript 2)
³ = GR + 3 (superscript 3)
¤ = GR + 4 (generic currency symbol?)
£ = GR + 4 (pound sign, UK currency symbol)
€ = GR + 5 (euro symbol)
¼ = GR + 6
½ = GR + 7
¾ = GR + 8
‘ = GR + 9 (opening single quote?)
’ = GR + 0 (closing single quote?)
¥ = GR + - (hyphen) (yen symbol; Japanese currency)
× = GR + = (multiplication sign)
÷ = GR + SHIFT + = (division sign)

« = GR + [ (open angle quotes)
» = GR + ] (closing angle quotes)
¬ = GR + \ (NOT symbol, a type of logical operator)
¦ = GR + \ ("broken pipe", related to | = SHIFT + \)
¶ = GR + : (paragraph symbol)
° = SHIFT + GR + ; (superscript "o", masculine ordinal, as in 2° = "segundo", 3° = "tercero". I haven't found superscript "a" yet.)
¨ = SHIFT + GR + ' (dieresis by itself)
ç = GR + , (comma) ("c cedille", used in French and Catalan)
Ç = SHIFT + GR + , (comma) (uppercase "c cedille", used in French and Catalan)
¿ = GR + / (open question mark)

There are other symbols and letters with other diacritical marks in addition to áéíóú that you can type using GR + letter or SHIFT+GR + letter. The letters may be used in languages other than Spanish or Catalan. On my computer I found these combinations for letters and symbols:

ä = GR + q
Ä = GR + Q
å = GR + w
Å = GR + W
® = GR + r ("registered" symbol)
þ = GR + t (lowercase letter "thorn", used in Icelandic)
Þ = GR + T (uppercase letter "thorn")
ö = GR + p
Ö = GR + P
ß = GR + s (German double-'s')
§ = GR + S ("section" symbol, sometimes used to mark footnotes)
ð = GR + d (lowercase letter "edh", used in Icelandic)
Ð = GR + D (uppercase letter "edh")
ø = GR + l
Ø = GR + L
æ = GR + z
Æ = GR + Z
© = GR + c (copyright symbol)
¢ = GR + C (a currency symbol for some countries)

There may be some other special characters hiding behind other key combinations.