From rest (with a gear selected and clutch depressed), you have to unlatch the handbrake, whilst at the same time gradually engage the clutch and deploy power via the throttle pedal. You have to ensure you don't go backwards on a hill nor stall the engine and quite a few other factors. You also have to be aware of what is around you and deal with weather etc. That's the simple description with only a few complications. At home we reverse hill start onto a narrow gravel track that runs at 90 degrees from the concrete parking stand - it is quite tricky! More so in a long wheel base Transit.
I drive two manuals - a car and a large van, and one auto - car, at the moment but I've driven most vehicles from 7.5t down, with or without auto.
An auto feels torque from the engine/wheels/conditions and your fuel input. You can floor the pedal to get going and then reduce power gradually as speed is picked up and eventually you know when the auto changes gear and can influence that accordingly - hard to describe.
In a manual you can see what is ahead and take action accordingly. You don't feel the actual torque but you can tell (with experience) from the engine noise and the feeling of acceleration.
It's all about using your array of sensors - eyes, hands, bum etc. and a shed load of experience. You do not learn that in five minutes and autos are not simply stop/start either.
I remember watching when Jules Bianchi had his fatal accident and I remember where I was when I read of Antoine Hubert had his fatal crash and I remember watching Romain Grosjean somehow walk away from an incredibly violent crash. Each one made me seriously consider giving up on the sport, but the racers racing and each crash has led to massive safety improvements.
I hope there is never another fatal or injury accident in motor racing. In F1 there was a long gap between Senna and Bianchi, let's hope the next gap never ends.
After 100 years or so burial plots should be recycled.