Time blocking is a time management method developed by Cal Newport, Author of Deep Work. The method asks you to divide your day into blocks of time. Each block is dedicated to accomplishing a specific task, or group of tasks.
In Journal it!, each day has a theme or themes (Work, Weekend, Holiday,...) which can be set manually or scheduled automatically. Each theme contain a set of blocks (Morning, Work, Evening,...). Each block has a start and end time. You'll schedule your tasks as calendar sessions into these blocks.
By default, your day either has Work or Weekend theme, depend on the day of week.
To customize the blocks of the default themes (Work, Weekend), from the main screen open the left panel -> Day Themes -> open the theme you want to edit -> edit the blocks.
In the Planner, tap the edit button on a day's title to start editing its themes and blocks. You can edit day structure for multiple days at once by switching to Advanced mode and select the days.
Other than editing day's structure one by one, you can schedule a theme to repeat at a certain days by creating Theme Schedulers. For example, you might have a Birthday theme, you can create a scheduler to repeat it once every year.
To create a theme scheduler, on the day theme screen scroll down to the bottom -> tap the "+" button on the Schedulers section -> set how you want to repeat the theme.
A theme can have multiple theme schedulers. You can deactivate or delete these schedulers to stop the scheduling.
When there are multiple themes scheduled for a day, the theme(s) with the Low priority will be ignored (the default Work and Weekend has priority value as Low).
When there are multiple themes scheduled for a day, the theme with the highest priority will be the primary theme. The day structure will contain all blocks from the primary theme plus unique blocks from the remaining themes.
You can customize the color, timer preferences (execution length and break length), and organizers (automatically added to calendar session created from this block).
To customize a block, on the main screen open the left panel -> Day Blocks -> open the block you want to customize.