If, for example, you change your router you will need to update the WiFi credentials in your monitor.
If the monitor can't connect to your WiFi it will generate a WiFi access point.
This will be visible the same way any other WiFi access point is visible on your phone, tablet or laptop

Connect to the Monitor's access point

The access point will appear as pm-monitor-xxxxxx where the xxxxxx is the same as on the monitor's label.
In the password box enter AirMonitor.
You should then be connected to the monitor.
Note: you might need to remporarily disable data access and auto-reconnect to your router on your phone as the monitor does not provide internet access and some phones will drop the monitor's access point and revert to data or your router

Navigate to the Monitor's home page

Open a browser and navigate to http://192.168.4.1
This home page will show you available networks.
Select your router's ssid and enter your router's password and click save.
The monitor will then try to connect to your router and remove its WiFi access point. If it does not connect, refresh the page and try again.

Find the monitor on your home network (LAN)

Your laptop/tablet should have now disconnected from the monitor and you will need to reconnect to your router if your device hasn't already done so.
If the monitor connected successfully it will be accessible on your home network at the address pm-monitor-xxxxxx.local
From this page you can configure the air quality level at which the red alarm light is shown on the monitor.
You can also see the current particulate matter concentrations and diagnostic messages which are helpful if there is a problem.
Data should start appearing on your dashboard within 5 minutes.