What's the difference between 「うまく」, 「上手に」 and 「よく」?

Question

What's the difference between 「うまく」, 「上手に」 and 「よく」, all seemingly meaning "well" in English?

Someone said that I should use 「よく」 rather than 「うまく」 in the following sentence. Can anyone explain why?

この文の意味は　うまく　よく　分からなかった。

I'd really like to know the difference between the 3 words, or maybe just some examples of where one is more suitable than another if possible.

Edit: Doing some digging through many e-mails, it turns out it wasn't 「うまく」 vs 「上手に」 at all as in the original question, but I think the other person clearly preferred 「上手」 over 「うまい」:

～さんのクラフトは うまそう 上手。

Answer 1

What's the difference between 「うまく」, 「上手に」 and 「よく」, all seemingly meaning "well" in English?

Quite roughly: 上手に means "skilfully." You don't skilfully understand a sentence, so that's why you don't say *この文の意味はうまく分からなかった.

うまく is quite informal in meaning "well" with a "skilfully" nuance. You use it for qualifying how you threw that bowling ball to do a strike, or how your sister sang at the karaoke.

よく is a formal or neutral way to say "well" as in "properly."

よく分かりましたか？