Enable all flows and:
1. In the "Dynamic DNS Client" flow, first tile, enter the subdomain (only the subdomain, not the entire hostname) to update
2. In the same tile, enter your duckdns token (it's listed at every login on their website)
3. Every time your active network changes (wifi or mobile data), it will automatically trigger the update process after a 30 sec waiting period. However, it will not update anything if your current ip is the same as the one already registered for your subdomain (to avoid abusing the service)
4. There's also a flow to create a shortcut/widget on the home screen, with the possibility to force the update.
Use case: you have a server/pc/service at home/office and you want to access remotely, but you want to protect it by applying "security through obscurity" techniques, aka. allowing only a limited number of IPs to connect to these. When out there in the wilderness of the internet, you almost always have dynamically changing IP addresses, whether because you are using mobile data, a wifi connection or even a VPN. So you need a DDNS and allow connections from your DDNS hostname, which you need to update. This is how you update it. Configure your router/gateway to refresh/resolve the IP for your DDNS hostname every "x" minutes, and allow the connection.
Enjoy
PS. Tested and working on Android v9 (Pocophone F1 with MIUI 10.2); attached some screenshots with the results (IPs are erased).
http://automagic4android.com/flow.php?i ... 87e04478dd