New to VPN

heybabe

So, got VPN added to my order this renewal time, people have said they're great, but I'm not sure if it's right for me.

I don't have an NBN / Cable / Adsl connection, such services in my area are quite poor from a speed perspective, so i only hotspot from my mobile phone that doesn't have a static ip.

I've installed the VPN on my laptop, mobile phone & tablet, but when i have them all on, i can't connect to the internet.

Do I only turn on the VPN for the device i'm using to hotspot the connection from?

If yes, does that mean I don't need the VPN to be running on my laptop (only on the device being used for the internet connection)?