Ah. Well, as I said before, it's like a question mark. I guess you could do it that way, it doesn't really matter. I don't use romaji all that much anyway, and Hiragana isn't supposed to have any spaces at all.
Y'all, it's basically "is" or "am" but grammar structure is different and stuff. You don't have to use it unless you're being polite. It's like an existence establishing word. Plus, with pronunciation, usually you just say it quickly and it ends up being "des". This happens a lot with words with "u" in them, but not all the time- usually middle or end sound.
Because ka is also supposed to go after the other sentence endings used in scenarios where desu wouldn't be right
Or that's what I've been taught