How do I watch my live stream on my phone without Wi-Fi
In theory, you just do it. When your phone loses access to the home WiFi network (you drive away), it should automatically access the cams over the cellular network.
There are reasons why this might not happen, like a poor data plan for your phone or your Internet; or you are someplace like a cruse ship that limits those types of connections because they don’t have the bandwidth for it, but in general it should be transparent and automatic.
To test if you have an issue or not, just turn off WiFi access on your phone and run the app to see if you can still see the cameras. Note this definitely wouldn’t be the preferred method of accessing the cameras because of the cellular bandwidth it uses!
I routinely watch my cameras at home (where the cameras have WiFi) with my phone when I am away from home (and therefore have no WiFi on my phone). Absolutely no difference in how you watch a camera via your phone. In the background of course the data is getting to your phone via your cellular data instead of via WiFi, but that makes no difference in how you watch your cameras.