how to show "in stock" or "outr of stock"?

I need to show "in stock" message and "out of stock" when the item is not available.
How could I do this?

That's already done automatically if you set a quantity in your products. A quantity of 0 will display "out of stock". A quantity greater than 0 will display the quantity left with a translation text that you can override if you want it to be "in stock".

Could you explain where I find this control please?

The quantity option is available on each of your product's edition page on your back end.
For the translations you can change them as explained there:
www.hikashop.com/en/download/languages.html#modify

I dont want Hikashop to show "in stock" "out of Stock" or the quantity of products left, but I do want to specify the number of products left in the backend for my own info and for Hikashop to automatically not show the product when its out of stock. But i dont want to show this info to the users. As You can see now in my shop, for every product that I specify a quantity, it shows up as "1 unidades disponibles" which is the units available, I dont want this to show up.
How do I do this, I cant find the option to disable this?

If you want to hide the messages on the front end, you can add the CSS below in the front end CSS file of HikaShop that you can edit via the tab Display of the configuration:

.hikashop_product_stock_count, .hikashop_product_no_stock{
display:none;
}

I did that and its still showing up..?¿
galeriadeartepedropena.com/arte/cuadros/12-pinturas
What am I doing wrong?

Ups, my bad...it works
I had to empty the caché memory.