How can I create a hostname?

I've study below link, but I couldn't understand this hostname part.
https://bagisto.com/en/how-to-create-multiple-websites-in-bagisto/

How can I hide this square button?

And What is the purpose of this button?

@devansh419
I want to append a few fields to this array.
So Where do I need to make changes?

@Vaishali-Agarwal Thank You

@Vaishali-Agarwal

I created 2 new Inventory Sources [Shana and Shana2]

Every time I have to select new Inventory Sources in channels.

Is there any way to take all sources by default for one particular channel.

@Vaishali-Agarwal
Thank you.
Is there any way to take all sources by default.

For example;

I've created 2 Inventory Sources

Go to edit in Denim Jacket product with 158 id [You can go to any simple product]

Now, if I set the first store value to 0 then the product goes out of stock

The product still has 200 Quantity

but product goes to out of stock

$product array in product detail page

Basically, I want to add extra fields to this $product array

product detail page