Botnet attacks are a series of computers/devices that work together to produce a malicious attack to a user.
Here's an example....
Wow! A new email! It has a link in it and says that I must click it!
Click this Link!!!! www.coollink.com
press to exit
The computer freezes....
And the computer starts taking a significant amount of time to load.
Oh no! My computer turned off and now I have to restart it!
This example shows botnets working with a DDoS attack. The botnets helped carry out the malicious attack in order to overflow the server with too much information, resulting in the slowing down of the computer. She could've prevented it by not clicking on the link and installing an anti-malware software beforehand.
So, remember that a cyber attack can happen to anyone at anytime,but if the right precautionary measures are taken, you can prevent any of this from happening.