[L0aD1nG]

You might want to point out that if ivs are not being re-injected to the ap you might have to deauthenticate a client that is already associated with that ap. But remember do it to many one time it will be a DoS to that client.

Code:
aireplay-ng --deauth 10 -a (bssid) -c (client) ath0

Well this is proven not to be good technique deauth attack should be single in the start cause there is a chance the router be "smart" enough to understand that you spaming deauth packages and then never give you the Handshake. (TRUE STORY)
So better try 4-5 times with breaks :

Code:

aireplay-ng --deauth 1 -a (bssid) -c (client) wlan0

Before you spam it... I just saying...


Now on the topic:
This tutorial has typos on commands(like ath0 probably means eth0, or more likely wlan0), it also doesn't have nice order on how to do the things you need to do with aircrack suite. We have better tutorial from this about aircrack if I am not mistaken. Avoid reading this one which in my opinion isn't well written and also isn't needed.

"i will explain you how to crack Wifi or wireless password in just 10 to 15 minutes"

LOL you can't know on how much they will do this, its depended on many things...For example a WEP with like 30 digits password without good signal could take even 2 days... Modify this please.