How does shpock actually work?

[Bbbely]

So I just set up an account and in my shpock wallet I have £0 available to withdraw and £0 pending. Do I need to link to a bank account at all? Or if I sell something then would I get something in “available to withdraw” which I could then use to sell?

Sorry once I ha e sold something b can I then use the money made to buy something? So I don’t actually need to link to bank account at all?