Stock quantities and options

In E-shop I noticed a peculiar thing.
In my catalog I have some items with options (e.g. lenght or size).
If in options tab I indicate I have in stock 1 piece with the option length 2 mt. in front store, when customers select that option E-shop writes that the quantity in stock is that indicate in the back store in data Tab, in this case 0.
If in back store, in the Data tab I indicate that I have 1 piece and in option tab I let the quantity 0 for all the options, in front store the customer will always have 1 item available in stock, regardless of the options he chooses.
Can you explain exactly how to use properly the function of inventory management.
Thanks in advance.

Hello Andrea,

Currently, then quantity show on the product details page is the main quantity under Data tab. However, when customer add a product with option values to the cart, the quantity in the cart will be the combination between quantity under Data tab and quantities of option values.

Sincerely, Giang

Hi... My query is also related to length
I would like to use the length feature you have - especially for the filter portion as the client sells rope at different lengths.
It is only in meters though. How do i make it display as meters instead of centimeters

I tried joomla's Language Override but that did not work

I figured it out under System, Lengths

That's fine!
Sincerely, Giang