We used to pray the Maghrib prayer with the Prophet (ﷺ) when the sun disappeared from the horizon.
Sahih al-Bukhari Book 9, Hadith 38
← Previous Hadith The Prophet (ﷺ) used to pray the Zuhr at midday, and the `Asr at a time when the sun was still bright, the Maghrib after sunset (at its stated time) and the `Isha at a variable time. Whenever he saw the people assembled (for `Isha' prayer) he would pray earlier and if the people delayed, he would delay the prayer. And they or the Prophet (ﷺ) used to offer the Fajr Prayers when it still dark.

Sahih al-Bukhari Book 9, Hadith 37 Next Hadith → The Prophet (ﷺ) prayed seven rak`at together and eight rak`at together.

Sahih al-Bukhari Book 9, Hadith 39