When and how is the Duha (Kusluk) prayer performed?

The Duha (Kusluk) prayer is a voluntary prayer that can be performed starting about 40-50 minutes after sunrise until approximately 10 minutes before the noon (zuhr) prayer. The Duha prayer, which is highly encouraged in hadith sources, can be performed in units of two rak‘ahs, up to twelve rak‘ahs. (Muslim, Salâtü’l-müsâfirîn, 78-84 [719 ff.]; Tirmidhi, Witr, 346 [473]; Ibn Majah, Iqamat al-Salawat, 187 [1380]; Bazzar, al-Musnad, 9/335 [3890]; al-Fatawa al-Hindiyya, 1/112)

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu