I am selling the skins on the market. It says "waiting for confirmation", and I have steam guard activated but i still don't see it on my steam app on my phone.
First off, ensure that you're logged in to the same account.
You can do so by going to Account Details and checking if username matches the one on PC:
Secondly, ensure that you're using Mobile Steam Guard and not Email Steam Guard, which'd email you the sell approval.
Thirdly, if you are sure that you're using Mobile Steam Guard, try pressing the refresh button on top right on confirmations.