1st Step :- Find a vulnerabale website ....
I Found This website
Now Lets Start ..
Open havij and copy and paste infected link as shown in figure
Now click in the "Analyze"
Then It shows some messages there....Be alert on it and be show patience for sometime to find it's vulernable and type of injection and if db server is mysql and it will find database name.Then after get it's database is name like xxxx_xxxx
In that Just put mark username and password and click "Get data"
Bingo Got now id and pass that may be admin...
The pass will get as md5 you can crack it also using this tool as shown in figure...
Now Find Admin Panel and Login with Your Crashed Username & Passwords !