How many times a day a does a Buddhist have to pray and at what time of the day?
Pray any time you want to in anyway you want to. One does not pray TO anyone or thing. One prays for balance, clear consciousness, compassion and empathy. The Buddha or another spiritual model may be invoked for the qualities one intends to strengthen through prayer. Buddhists use chanting but it isn’t a hard rule. Whatever works. Getting a mantra from a teacher you have spent some time with (quality of time matters more than length of time) is a VERY strong prayer.