The backlog is your best tool when planning any project, it allows you to arrange cards in a hierarchy to break down goals and categories into small workable items. Starting with building the overall vision, breaking your ideas down to epics and eventually when they're ready to be executed, into user stories that can be committed to teams.
As seen in this image we have added parent items in bold, these can represent goals, epics, themes, categories, and so on. Then we have broken these down into child items by hovering the cards and pressing the tab key. The child items represent your workable cards or user stories that you move across your board. Tip: By enabling the Relations column in the backlog everyone can easily overview the status of all items thanks to the relations that will be shown here.
If you have multiple large-scale parent items, and you would like to work on them in a different board, but have the connection with the backlog item, you can Break down to board. The option creates a board having the connection to the selected item where you can work on that card flow, set up its own backlog or track progress,
Sometimes user stories consist of sub-tasks or a range of criteria that need to be completed, this is where checklists can come handy. By breaking user stories down with checklists and checklist items, not only do you make it easier to see the progress in detail but you can also distribute sub-tasks to different people by mentioning them.
If a checklist happened to grow a bit too long or if you would rather add the tasks as cards to a board, you can convert entire checklists or individual checklist items into cards for more detailed tracking.
After you've converted an item it will disappear from the checklist and be added as a new card to the location you have chosen. From there you can either break the card down further by adding child items or by creating a new checklist within the card.
Sometimes it can be hard to estimate the scope of work at first. Now you know how to break down large items into child items and checklist items and also how to increase the scope of small items by converting them to cards 👍🏼
If you often repeat the same steps you can save checklists as templates. In the linked article you can also read about how to send checklists to other cards.