Accents are used to denote separate letters, so that one sound
always maps to one letter and vice versa. The "x-convention" is usually used to type accents online, since Esperanto doesn't use 'x' in any other context - it looks very weird, however. For example, the following:
Estas ĉar ĝi estas "nenaturan" kaj homoj ne volas lerniĝi, malgraŭ ĝi estando facile lerni kaj regula.
->
Estas cxar gxi estas "nenaturan" kaj homoj ne volas lernigxi, malgraux gxi estando facile lerni kaj regula.
Your translation is very close, and a speaker would understand your point, but there are a few mistakes. None of them are actually with grammar - it's all word choice.
The "ki-" part of a correlative denotes an interrogative tense, and "-u" refers to individuals (living things), so "kiu" roughly means "who" as a question, e.g. "kiu ke?/who is that?". "Tio" would be more appropriate, as "ti-" indicates a demonstrative tense and "-o" refers to an object.
I'm not sure about "cxapelito" - "cxapelo" means cap, usually in terms of a hat, so while "cxapelita" would be "previously capped", it'd work better (in a metaphorical sense) for accented characters. If you want to specify capital letters, you could use "literegojn" (-eg- being augmentative, so translated closely to 'large letter') or "majusklo" (this is a special word for 'capital letter' - try to avoid specific words unless necessary).
My translation of it would be less literal, in order to better get the main idea across (and I prefer Spanish-style adjectives, but that's entirely a personal choice):
"EK estas programo, tio asistas tajpi literegojn esperantajn."
Which translates more closely to:
"EK is a program that helps typing Esperanto capital letters."
You seem to have a grasp of the basic grammar, which is definitely a good start. When the grammar is mastered,
all you need to know are morphemes, suffixes, and affixes.