fluid dynamics - What is the real cause of the boiling (forming of bubbles) of water?

I've got a question about the boiling of water. I'm a first year physics student and from the Netherlands.

I've searched alot about the boiling of water and this confused me. Everyone said something else about the cause of the boiling. Let me explain it further.

Let's say you want to cook some eggs. You put on the gas. 1. As the temperature of the water increases, the evaporation increases. 2. When the evaporation increases, the vapor pressure will increase too. When the vapor pressure is equal to the external pressure, there will form a bubble.

So, my question is: is this a chain/link of causes? So the first link causes the next one? So the temperature increase causes the evaporation to increase which causes the vapor pressure to increase which causes the forming of a bubble (the actual boiling)?

I doubt if it is a link of causes (the one thing causes the other) because they happen at the same time. And in my opinion a cause happens BEFORE the consequence.

https://www.youtube.com/watch?v=CfagHzOtIDM In this video they say boiling has more causes. What are these causes?

When the boiling point is reached, there happen two things: - 100 degree celcius - vapor pressure that equals the external pressure

Are they both causes of the boiling (coming up of the bubbles)? Or is the vapor pressure that equals the external pressure the cause?