"Dw i'n mynd i Gymru rŵan."

Translation: I am going to Wales now.

[JayneMoore]

I put "I go to Wales now" :(

[Jonlang_]

Why? Would you say "I go to Wales now" in English? Probably not. As well as "translating" you must also "gloss":

Welsh: Dw i'n mynd i Gymru rŵan

Translation: I do [in the act of] to go to Wales now

Gloss: I am going to Wales now