How to set a condition for the availability of goods in Bitrix?

Question

1C-Bitrix

Hello, I have a question about Bitrix. How and where can I put down my own condition for displaying the message "Out of stock"? And where is the default condition? That is, for example, if there are less than 10 products, "Out of stock" is displayed.

Answer 1

$quantity= $arElement[CATALOG_QUANTITY];
Then just the conditions
if($quantity!=0 && $quantity<=10)