This article gives a step-by-step guide for managing "stock":

From the Order Track view, click on the Stock Control option.

This will open up the Stock Control view, from where you can control the "Availability" of both your items and the corresponding "Modifier".

Click on the "Modifier" of the item for which you want to change the stock of the modifier.

Additionally, there are search and filter options available on the item list view.

Search on Name

Enter the name of the item on the name field and hit the enter button. The system will search all the items and give you the matching results.

It is worth noting that the search option here supports both "partial" and "complete" searches.

Filter based on Category 

Select the category of the items on which you want to filter out the results. It is possible to filter by more than one category.

Filter by Stock Control

Filter the items by their current stock status, i.e. "in-stock" or "out-of-stock".