You questions are all answered in these (and other) threads and wikis:
Select Boot for K4 and Touch
simple kindle touch (and k4nt) debricking method
Kindle Touch Hacking wiki
Click the above links and read them.
For specific case details (including using fastboot for Mac), click the "Success Report" links in the simple debricking first post, and read the posts leading up to each success report. For more specific information, learn how to use the mobileread search tools.
AFTER reading the above threads and wikis, then you may ask any remaining questions (in a debricking thread, not a new thread like this).
You MUST invest the time, or you will not understand us when we try to help you. If you cannot invest the time, then invest the money to buy a new kindle and donate the bricked one to somebody who IS willing to invest the time to learn how to debrick it. If you do not want to invest the time or money, then install ONLY amazon approved software on your kindle, or hire somebody to put the unauthorized hacks and mods on it for you.