This will be advertised in stores. Any new Walmart.com account or preexisting Walmart.com account that has never used the app before can download the app, login, then choose their store location. If you don't have a store or are feeling generous, please pick the Neighborhood Market in area code 27012. The store with the most signups will receive a trip and each associate will receive $1,000. If you'd rather link your own store, go right ahead and immediately get $5 off your next order of $35 or greater. Or you can put in one store and change it later.
If you already have the app on your phone, your spouse can sign up and as long as it is a new account, they should be able to login. 10 minute mail is great for this assuming your spouse or imaginary significant other is without email. You'd probably need to use a new device (I assume their recording android IDs). Bluestacks is a great alternative for those without a phone.
To choose your store, once you have an account and login, when you hit the 3 lines for settings, it should have it under your name.
The $5 discount will appear immediately when you attempt to checkout as 'Walmart App'.
Other reasons to download the app are that it works as an in-store price changer. If you are looking for a deal on the clearance rack but it is in disarray, you can use your phone camera to scan the barcode and it will give you the price. You can also use it to check a stores inventory for an item and it will tell you where in the store the item is and if it is in stock.