New product or project development:
1. Create a new JIRA project
You need to have the project administration permission to do so.
In an organization, this permission will not be granted to many people.
You can give it a key. The key will be prefix of issues number for issues created in the project.
You can give it a unique icon, call Avatar.
A JIRA project is sometime mapped to "Product" within software organizations. A new product may be a "project", but when you have multiple releases and start maintenance cycles, you are developing and maintaining a product which is typically created as a JIRA project.
2. Create a Board
For a new development project, a new broad can be created for an existing JIRA project, or for a JQL, which is a query for collecting issues from multiple projects.
This is a very good way to run an "integration" project, when a project involves the teams that are from multiple product and from multiple organizations.
You can create multiple boards. Multiple boards can exist simultaneously. A board is actually just a view of the issues in different columns.