How to setup mysql with less letters

Can anyone help me out with the search. Mysql database stopped from fulltext search. Was trying Rhett´s answer:

I can confirm this is working after clearing the cache, here are the currently needed steps to do this.

• In your my.cnf or your mysql config file, (will vary depending on setup) add/edit the following line

• ft_min_word_len=3

   

• Restart mysql
• Rebuild search index in IPS4
• Run the first step of the support tool to clean the cached files mentioned above.
• Success! 

after this there is no changes. Can somebody do a walkthrough how to do every step. I´m using an own server and Putty ssh.