Create a standard access-list first for the allowed network/host with a Read-Only access on the SNMP service of router (global config mode):

access-list 10 remark SNMP Access List
access-list 10 permit aaa.bbb.ccc.ddd

Enable the SNMP service and assign the access-list with a Read-Only permission (global config mode):

snmp-server community joel RO 10