Login

All you need is your email address, there are no passwords.
Go to the Login page either register your email with a new account or use the recover option if you have registered previously.
After registering (or following the link in your recovery email), you will be automatically logged in and taken to your personal Wishlists page.
You should bookmark this page to make logging in easier.

Make it an App

If you are on your phone, click on "My Wishlists" then click on your browser's "Share button" and then "Add to Home Screen".
Now you'll be able to easily find it as if it were any other app.

Create and Edit Wishlists

From your wishlists page, simply use the drop-down to select or create wishlists. You can have as many as you want and you can share (or not share) with any number of Communities of which you are a member.
To add an item to the current list, click the button and fill in the information.

Communities

In order for other people to see your list, you'll need to be a part of a Community and share your wishlist(s) with those communities.
To join a Community, you'll need the Invite Code. Ask the Community creator for that or I can help too.

Share Wishlists

Choose the wishlist you want to share and click the button to choose which Communities you want to share it with.

View/Update Others' Wishlists

Go to your Communities page and choose a Community. You'll see all the wishlists that have been shared here. Choose any wishlist you'd like and you'll be able to coordinate with other people on this person's wishlist. The owner of the list will not see your updates but everyone else can!