I have no idea what is available in Cambodia! I use Near East brand taboule, but have bought the bulgar wheat and cooked it, many years ago, so I'm hoping someone will chime in with instructions. Refridgeratte for a few hours.
After the wheat is rehydrated and cold, I chop large amounts of parsley, mint, tomatoes, cucumbers, green onions or chives. The amounts don't matter, just do it to taste. The cuisines of most Southeast Asian countries are heavy on herbs, so go wild with them. I toss them all with a tablespoon or two of good olive oil, but then I'm going for a Meditteranean flavor. A drop or two of toasted sesame oil and some seeds, and some cilantro would change the character entirely and be delicious.