Problem with product quantity

Dear users,
I am using OceanWP theme and the woocommerce.
I have been trying to solve this issue on my own for quite a long time now and I gave up.
I created a one-product store and when I go to the product page, there is no quantity option(i would love to have +/- and a quantity field next to the add to cart button). Generally, I want to have something close to that:
Plus and minus quantity next to cart

Another issue is that whenever I try to add the same product more than once to my cart it displays me the communicate “you cannot add another xxx to your cart”. I would love to have it possible to add the same product multiple times without any limitations.

These are my two issues. I would be glad if anyone could have helped me here.
Best regards and thanks in advance.

The page I need help with: [log in to see the link]