when you found the containers give the items you want to restock a - (minus) before the value
and you take the armor from the armorlist and draw it to the opened container menu to add it.
Which value? I'm not sure which value you're talking about, or where to find this value
Also, sorry but I don't understand that second part.
I've never worked with this editor and I have no idea what you're talking about, sorry but you'll have to explain a lot more than that and go into much greater detail.
I don't know this specific trader, you mention. But for a trader you must find and select the cell, where he is located. When you choose this cell, you will see the cell and a list of items placed in the cell. In this list the items have a type, where you should look for the items of type containers (which is crates, chests etc) and ownership set to the trader. All items, which has ownership set to him are sellable and make up his stock (he might also be carrying sellable items, but we disregard that from now).
You should click on a container on the list to see a window with the properties of it. This should include a list of the items placed in the container and this is the list Sister mentioned. For each item in the list there should be a number indicating how amny of this items are contained in the container.
If you open the armor tab and look for nordic mail or other items you want to add to the trader, you drag it to to the list of items for the container, you just have opened. You can then adjust the number of each items to -2 or similar nagative number.
In the properties for the container, there is also a weight attached saying much weight the container can carry. I don't remember if that might need to be raised to hold the items, or the weight only matter if you put items into the container while playing.
The description above is from memory, but I think it's right.