When you want to share something with a receiver you start in the app by:
Choosing the location
Adding the receiver (Recipient)
Opening the door and leaving the item in the Sharebox
To perform these steps you would normally start in the app by pressing the Plus sign to make a new reservation.
A list of locations appear and if you have location services active on the phone you will have the nearest Sharebox location on top of the list. You can also switch to a map view to find the closest location.
After choosing the location you will be shown the "New restervation screen".
Hit "Add recipient" and choose from your contact list or enter the mobile phone number of the receiver.
Hit "Reserve Sharebox" to finish the prosess, give your reservation a name and open the Sharebox so you can leave the item for your receiver who will now receive a text message with notice of your transaction and info on how to open. (either with the app or by sending a text message)
Get a full overview of the locations by looking at the Sharebox webpage
The Locations Page will both show you a map of all the locations and has a search function.