Want to run the master nondisruptively when replicating with MySQL

https://dev.mysql.com/doc/refman/5.6/ja/replication-howto-masterstatus.html

We are proceeding with the replication by referring to the above URL, but it was written that you should type the following command.If you type this command, you will not be able to load the current running master server.

FLUSH TABLES WITH READ LOCK;

I would like to replicate the master server without interruption. Could you tell me a good way?