Install p5-Net-SNMP to use the optional SNMP-based monitors.

Before starting munin-node, you should create symlinks in
${SYSCONFDIR}/munin/plugins as described in the manual (manually or
using the output from munin-node-configure --shell), adapt
${SYSCONFDIR}/munin/munin-node.conf if necessary (e.g. if a remote
server will query this node).