Sokuon (っ)

Sooo...
I'll explain the "Sokuon", it`s not difficult.
It indicates a double consonant.

For example:
"nippon" is more formal than "nihon".
So...how to write "nippon" in Hiragana...
When typing it, the Sokuon appears automatically.
にっぽん
ni + Sokuon + po + n = nippon
(note: of course that`s a bit weird, I guess no one writes "にっぽん" instead of "日本", but hmpf, nevermind, it's only an example to explain how the Sokuon works)

Another example:
"issho (ni)" (synonym for "tomo ni")
いっしょ
i + Sokuon + sho = issho

わかりましたか？？　いい！！