What do you mean? Please tell us what you've done.
You need to search for the user/group first of all and then highlight the entry and click the arrow to move it to the other table.
Older version of WAS but relevant
https://www.ibm.com/support/knowledgecenter/SSAW57_8.0.0/com.ibm.websphere.nd.doc/info/ae/ae/tsec_tselugradro.html