Learn Italian: Gli insetti non sono qui. - The insects are not here.

In Italian, you use gli (instead of the standard i) for masculine plural words that start with a vowel, a z, or an s followed by a consonant. Since insetti starts with a vowel, it gets gli.

How do you pronounce gli?

It does not sound like the English word "glee"! The Italian gl makes a sound similar to the "lli" in the English word "million". Try pressing the middle of your tongue to the roof of your mouth as you say it.

Doesn't sono mean "I am"? Why is it translated as "are" here?

The verb essere (to be) is a bit quirky: it uses the exact same word, sono, for both "I am" (io sono) and "they are" (loro sono). Since the subject here is gli insetti (a "they"), sono means "are".

Why is it non sono and not sono non?

In Italian, the negative word non must always go directly before the verb it is negating. While in English you say "are not", in Italian the order is literally "not are" (non sono).