If you store your SQL statements in a source file, you can use the RUNSQLSTM command to execute the source file as an SQL script.
REGISTER or login:
/* This creates a source physical file, which can contain source members (in your case SQL scripts) */
/* This should give you an empty list of source members */
Press F6 (Create) to add a source member, give it a name and description, the source member type isn't important for an SQL script, but you could use SQL so you know it's an SQL script */
You should now be in the SEU editor. Type in your SQL commands here and press F3 to exit and save when you're done.