How to ensure that I am using the Wi-fi, instead of cellular

[louiswho]

New to Android. Got S7 Edge, Added Chromecast, Sling. When at home (or anywhere), and I want to use the Wi-Fi (so as to not use up my data plan), how do I ensure that I am using the Wi-Fi, and not my data plan. What ensures that my phone will use the Wi-Fi. If it detects that it has access to Wi-Fi, does it just automatically use it?

 

[N4Newbie]

If you have a Wi-Fi connection (and it doesn't have a tiny "x" in the signal meter), then your phone will use it for data. The phone will only use cellular data when there is no other data connection available.