"o" is like the "o" in "rope"

"ko" is like the "co" in "cope"

"so" is like the "so" in "soap"

"to" is like the "to" in "tofu" (obviously)

"no" is like the "no" in "note"

These are the most similar sounds in English, but it's not exactly how you pronounce it because Japanese is pronounced very differently than English. The Japan Channel has YouTube videos on Hiragana and Katakana, I recommend checking either of these out in order to help you understand how to pronounce each of those sounds.