I bought a new phone last wednesday which was set up for me in the shop and they transferred my sim card to the new one.   I've already been back there once as I could not access WhatsApp.  They did that for me but I am unable to send anything as I cannot access my Wi-Fi.  I don't really want to go back to shop, so can anyone tell me how? 
Words of less than one syllable would be great!

Check in settings, WiFi is switched on and you may need to connect and possibly put your router password in.  Does this help?

Sort of...  I have many numbers on my router and do not know which one to put in, or of I ned all of them?  I have tried them, plus the Password but it's not happening.  I have tried taking a photo of it but I'm unable to take photos...
I HATE TECHNOLOGY!!!!!

Ask who supplied your router what your password is.

Very kind of you to try Roscoe...I gave up a long time ago 

If you look on the bottom of your router and there is something described as a WLAN KEY - that is your router password 

Yippeeeeeeeeeeeeeee!  Just found a different number on my router in incredibly small print, looked via a strong magnifying glass, put it on my new phone and I am connected!!!  I now have to contact all the people who've sent me messages over xmas...
Thank you all for your advice.  Ive been trying since 24th to sort it!!!

Yeah!! always better to ask a 10 year old to fix it

Write that password down and stick it on top of your router. 

I'm ahead of you Roscoe!  Already done....

 

All I need to do now is work out how to delete the masses of photos I took of my leg while I was working out how to send the ones I'd taken that I wanted to send. 
All this excitement, I should sleep well tonight