Every climber asks about summit night and most descriptions are either too heroic or too vague. Here is roughly how it goes from Barafu.
Around 6pm: an early dinner you do not want
You arrive at high camp in the afternoon, eat early, and try to sleep at an altitude where sleep does not come easily. Most people lie awake. That is normal and it is not the disaster it feels like.
Around 11pm: tea and getting dressed
A guide wakes you. There is tea and biscuits. Getting dressed takes far longer than you expect because you are putting on every layer you own inside a small tent in the cold.
Midnight: walking
You set off into the dark in a line of head torches. The pace is slower than seems reasonable. It is meant to be. You are on scree, switchbacking upwards, and there is nothing to look at except the boots in front of you and, if you look up, an extraordinary number of stars.
2am to 5am: the long middle
This is the part people remember. It is cold, it is repetitive, and your world narrows to the next few steps. Your water may freeze if the bottle is not insulated or upside down. Guides will check on you often and may start singing. Let them.
Around dawn: Stella Point
You reach the crater rim as the sky goes orange behind Mawenzi. Many people find this the emotional moment rather than the summit itself. There is usually tea. The hard climbing is done.
Then: Uhuru Peak
Another 45 minutes to an hour of gentle walking along the rim to the highest point in Africa, at 5,895 metres, past the glaciers. You will have less time up there than you imagine, because standing still at that altitude is not a good idea.
Then the part nobody mentions
You still have to descend, all the way back past high camp and on down to a lower camp for the night. It is long and your legs are finished. This is where trekking poles earn their place in your bag.
What helps
Eating something at every stop even though you do not want to. Keeping spare batteries warm inside your jacket. Not thinking about the summit. Thinking about the next hundred steps.