How to fix your device's IP

I fixed the IP address of my mac mini the other day and I thought I'd better write myself a reminder of how to do it! Please let me know if there are any errors or better ways to do it.

1. Find your router's IP address
   This can usually be done by googling 'what is my ip address' on a device using the router's wifi network.

2. Log in to your router
   This can be done by opening a web browser and using the router's IP address as the URL. You will probably be asked to log in; if you don't know the credentials consult your router documentation or see if there's a default password suggested on the login screen.

3. Find the device in question, note its IP, and fix it
   In my case, I had to go through the menus to find the list of devices (called 'clients') connected to the network. Next to each device there was a checkbox that said 'fix ip' or something like that, and I just had to tick it and I was done
   Note: each router menu is different so YMMV

Now that device will always have the same IP address on that network. (Otherwise it changes all the time apparently)