How to use WhatsApp through VPN?

Having read these posts, I asked above question:
Secure WhatsApp in an unrooted FP3.

I’m still struggling whether or not to continue using whatsapp when I properly start using my fp2. Should I replace it with a ‘better’ app or should I use it in a way that minimizes the effects of the downsides of WA ( how is my data used?)?

I’ll investigate how to use vpn and what the actual advantages are.

So at this point I didn’t try out something yet.