I don't use the bundled mysql, so I can't give letter-perfect instructions, but hopefully this is close enough.
So let's assume you have two installs… /opt/alf3.4.a/ and /opt/alf3.4.d/ (I don't know what you called them, but this is just an example for you)
Basically, you want to backup the mysql db from /opt/alf3.4.a and restore it to /opt/alf3.4.d
Shutdown Alfresco.
1) Go to the /opt/alf3.4.a/ directory. First we will start the bundled mysql db: /opt/alf3.4.a/mysql/scripts/ctl.sh start
2) Next we will backup the previous alfresco db to a file. You will need the mysql root password you were prompted for when you installed this… substitute it for PASSWORD: /opt/alf3.4.a/mysql/bin/mysqldump -uroot -pPASSWORD alfresco > /tmp/alfresco.sql
3) Confirm that the database dump is there: less /tmp/alfresco.sql
4) Once you've confirmed that you have data, shutdown the previous bundled-mysql: /opt/alf3.4.a/mysql/scripts/ctl.sh stop
5) Start the new bundled-mysql of the 3.4.d install: /opt/alf3.4.d/mysql/scripts/ctl.sh start
6) We will now drop that database, and then create a blank one: /opt/alf3.4.d/mysql/bin/mysql -uroot -pPASSWORD
show databases; (one should be called 'alfresco')
drop database alfresco;
create database alfresco;
quit
7) Next, we'll restore the backup we made into this new/empty alfresco database: /opt/alf3.4.d/mysql/bin/mysql -uroot -pPASSWORD alfresco < /tmp/alfresco.sql
8 ) When it is done, shutdown the bundled mysql: /opt/alf3.4.d/mysql/scripts/ctl.sh
9) Start the new alfresco, and then watch the catalina.out logfile; /opt/alf3.4.d/alfresco start; tail -f /opt/alf3.4.d/tomcat/log/catalina.out
Hopefully this is good enough to get you through. Finally, I don't means this as a criticism, but I think you need a little more general background knowledge of Linux under your belt if you are going to be supporting/using this.
Good luck
