There are multiple ways to create a collection in Stacks. The easiest way is to look for the + button in the sidebar next to the Collections header. Click on it, and you will be presented with a dialog where you can enter the title and description of your collection. You can also add an emoji to your collection to make it more visually appealing.Optionally, you can mark the collection as public. That way, anyone with the link can view it. This option is turned off by default.