Understanding how to use when and while becomes more
complicated when you realize that native speakers often
use when for while, but they don't use while for when:

OK:

When / While I was driving home, I ran out of gas.

I ran out of gas when / while I was driving home.

Not OK:

*While I ran out of gas, I was driving home.

*I was driving home while I ran out of gas.

_______________________

OK:

When / While Jim was working in Chicago,
he bought his first car.

Jim bought his first car when / while he was
working in Chicago.

Not OK:

*While Jim bought his first car, he was working
in Chicago.

*Jim was working in Chicago while he bought
his first car.

_______________________

Not OK:

*While Julia fell down, she hurt her ankle.

*Julia hurt her ankle while she fell down.

Not OK:

*While Diego lost the race, he almost cried. /
*Diego almost cried while he lost the race.

_______________________

OK:

When / While the chairman was speaking,
everyone was listening intently.

Everyone was listening intently when / while
the chairman was speaking.

OK:

While / When Jane was driving to work,
she was planning her day.

Jane was planning her day while / when
she was driving to work.

______________________________________________

Special Note:

Notice that when and while are not always interchangeable:

OK:

When Julia fell down, Fred helped her get up.

Fred helped Julia get up when she fell down.

Not OK:

*When Fred helped Julia get up, she fell down.

*Julia fell down when Fred helped her get up.

OK:

When Diego lost the race, he almost cried.

Diego almost cried when he lost the race.

Not OK:

*When Diego almost cried, he lost the race.

*Diego lost the race when he almost cried.

OK:

While the chairman was speaking, everyone was
listening intently.

Everyone was listening intently while the chairman
was speaking.

Not OK:

*While everyone was listening intently, the chairman
was speaking.

*The chairman was speaking while everyone was
listening intently.