Она не только не вставила диаграмму на слайд, но и забыла выделить заголовок.

She not only did not insert the chart onto the slide, but also forgot to highlight the heading.

Breakdown of Она не только не вставила диаграмму на слайд, но и забыла выделить заголовок.

• не: not
• не только: not only
• но и: but also
• она: she

Questions & Answers about Она не только не вставила диаграмму на слайд, но и забыла выделить заголовок.

How does не только ..., но и ... work in this sentence?

It is the Russian equivalent of not only ..., but also ....

So:

• не только не вставила диаграмму на слайд
• но и забыла выделить заголовок

means that two things are being combined:

1. she did not insert the diagram onto the slide
2. she also forgot to highlight the title

This structure is very common in Russian and works much like English:

• Он не только опоздал, но и забыл документы.
  = He not only arrived late, but also forgot the documents.

In your sentence, the first part is negative, which is why it looks a little more complicated.

Why are there two не in не только не вставила?

Because they do two different jobs.

• The first не is part of the fixed pattern не только ..., но и ... = not only ..., but also ...
• The second не negates the verb вставила = did not insert

So:

• не только = not only
• не вставила = did not insert

Together:

• не только не вставила = not only did not insert

This is normal Russian. English also does something similar:

• She not only didn’t insert the diagram, but also forgot to highlight the title.