Downloarding WhatsApp on a mobile (Samsung) How?

Hi fellow mailers... It sounds simple, but for an electronics 'dummy' like me; it's difficult!
So, in dummy language; How do I add someone to my WhatsApp contacts? I ask around but nobody seems to know? In the past I have got over this problem by asking the person concerned to WhatsApp me; I then automatically have it in 'contacts'. There's nothing on the web that mencions 'Adding' somebody to a contact. Which must all be good info, and no doubt there are many that would befefit from it...
thanks iv advance ....
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Hi gerry
If you open up WhatsApp, at the bottom right hand side, there is a green circle, press that, it will take you to next page, press contacts and it will let you add new numbers

Thanks for that brynkaz. I'll give it a go.

Go on the square box with a pen in , it will come up add new contact, simples

anyone know how to install Whatsapp on to a Kindle without using Google Play please

Another way you can do it on a Samsung (not sure about others) is if you already have the contact in you phone, but not in WhatsApp open up the contact from your contacts list, click 'Details' and the under the phone numbers etc click 'View more'
Is they are using WhatsApp you will see the WhatsApp logo next to 'Message' and 'Voice Call' options

All ways make sure your when you add a contacts phone number it has the country code in front ..i.e 0034...0044..it dont seem to work unless that is on your contacts number in your phone contacts list ..