Can't buy product - how to fix?

Up and running as of yesterday but having some problems. I’ve tried to do a tester and I’ve searched for our product, clicked on it and seen all the variations (different colours in this case), the see all buying options button is there so I followed that and was taken to another page where the ‘add to basket’ button has shown up. I clicked on a product and hit add to basket but it just took me through another page that said ‘basket is empty’.

I’m not sure what I’m missing as I’d previously been told everything looked fine to go live and now we are but no one can buy our products.

Can anyone help with what I’ve done wrong for this to happen?