The explain tools (db2expln and dynexpln) are located in the misc subdirectory of your instance sqllib directory. If db2expln and dynexpln are not in your current directory, they must be in a directory that appears in your PATH environment variable.
The db2expln program connects and binds itself to a database using the db2expln.bnd file the first time the database is accessed. The db2expln.bnd file is in the bnd subdirectory of your sqllib directory.
To run db2expln, you must have SELECT privilege to the system catalog views as well as EXECUTE authority for the db2expln package. To run dynexpln, you must have BINDADD authority for the database as well as any privileges needed for the SQL statements being explained. (Note that if you have SYSADM or DBADM authority, you will automatically have all these authorization levels.)