Using a server is a quite good solution if you're new to unlocking.
It's not that easy to find all the stuff you need and you will have to read tutorials etc when you wanna do it for free and on your own.
But if you choose the free version: BACKUP YOUR GDFS FIRST!!!
There are very few possibilities to bring your phone back to life once you have damaged the GDFS of your phone.
SE Tool Lite (free) is able to backup GDFS and it's no more difficult than pressing one button.
So if you mess up your GDFS you still have a backup. Each GDFS is unique (that means you can't simply download any GDFS and flash it to your phone - it won't work).