What a task holds
A task has a title, a status, an optional assignee, an optional due date, a description, and whatever custom fields your workspace has defined. It can carry subtasks, notes and file attachments. Nothing except the title is required, which is deliberate: capture first, tidy later.
A due date in Cretask is a day, not a moment. The date you set is the date everyone sees, wherever they are, so a task due Friday does not quietly become Thursday for a colleague in another timezone.
Subtasks
A subtask is a task that belongs to another task. It has its own status, assignee and due date, and it shows up in the assignee's own lists like anything else, so work handed to someone as a subtask is not work hidden from them.
Cards and rows show a subtask count rather than a progress bar. Two of five done is a fact; a bar implies a precision that a list of unequal jobs does not have.
Projects
Projects group work and give it a home in the sidebar. A project has its own people list, which answers the question of who is on this work, joining the people explicitly added with whoever is assigned a task inside it.
Any member can create a project and edit one. Deleting a project is an admin action, because it takes everything inside it with it.
The pages that cut across projects
Today, Assigned to me and Created by me read across the whole workspace rather than one project. They are the answer to what should I do now, which a single project view can never give you.
Each of these pages remembers its own view independently, so Today can be a list while a project you are running is a board.