Scanners are a special type of Metasploit module that attempt to find computers on a network running specific pieces of software. All of the scanner modules available on the store are free, so create an account, load the plugin, then sync and you will have direct access to them immediately.
Unlike exploits, which work on a single host at a time, scanners take a network range to scan. You can change how fast are slow these scans are performed by changing the number of threads Metasploit will use while scanning. If you are familiar with scanning networks with nmap or other similar tools, picking up using the scanners in Metasploit will be straight-forward.
Here is an example scanner run finding a Splunk instance on the network.