Деепричастие is a special form of verb which includes features of a verb and an adverb. So we use it as an additional action to describe the main action. Look at the example:

• Мальчик читает книгу и слушает музыку.

Or we can say:

• Мальчик читает книгу, слушая музыку.

It has the same meaning but as you can see in the second example the verb “слушать” has a different form. This is adverbial participle.

So as you can see from the example we use it when someone is doing two things at the same time:

So everything you have to do is just to replace the infinitive ending  -ть of one of two verbs with the ending -я.

Here are some more examples:

• Работая целый день, я думал о тебе – I’ve been thinking about you during the whole work day.
• Он шёл улыбаясь –  He was walking and smiling.
• Я читал книгу, смотря телевизор. – I was reading a book while I was watching the TV.