Please explain how to use an Inpost locker to return a Vinted item

[Domoda]

Apologies for being clueless. I have to return an item on Vinted, the seller has agreed the return and I have printed a label, it says I have to send the parcel via an Inpost locker.
Please can you explain literally what I have to do..I know how to locate a locker, I've had a look on the Inpost website which tells me the local locker locations with space. I will print the label and attach to the parcel and go to the locker....and then what?
Do I need to download the Inpost app?
Thanks

The lockers have a barcode scanner on them with a touch screen. The touch screen talks you through it. Essentially you can the barcode, select the size of parcel, and then a door magically opens and you pop your parcel in. It's very easy and the instructions it gives you are very clear.

It's super easy. When you get to the inpost locker it will ask you to scan the barcode on the printed label. Then the door opens and you put it in. Literally takes seconds :) No app needed

They're actually great.
Try to select the no print option, unless you have a printer.
Show up at the locker- the screen will prompt at each stage.
You basically select post/ deliver/ send (can't remember!)
Then say whip size locker you need.
Then wait a moment for a locker to pop open.
Put parcel in
Tap on machine to say "I am finished "

Only problem is if they are full- but the app tells you where the nearest space is.

Brilliant, thanks!