By default periods are just numbered. To label them — "Homeroom", "Reading", "Prep" — turn on the title period, which adds one extra row or column reserved for headings.
Turn on the title period
- Click Planbooks, then Edit next to your planbook.
- Click Show Advanced Options.
- Tick Title Period.
- Click Save.

What you get depends on your orientation. With days across the top, it adds a column down the side, so each period gets a heading. With days down the side, it adds a row across the top — the checkbox's hint changes to match.
Name each period
Click into a title cell and type the name.
Set it to repeat, or the name shows for that week only.
A title cell is an entry like any other, and every entry defaults to once. Type "Reading" without changing that and you've labelled one week — every other week stays blank, which looks like the name didn't save.
In the editor, change This entry should appear from once to weekly, then choose for all weeks:

- for all weeks — the name applies to the whole planbook, which is what you want for a period you teach all year
- going forward — from this week on, for a subject that starts partway through the year
Do that once per period. See Repeat a plan across the year for how the repeat options work generally.
Names entered here follow the period when you reorder your periods, so you don't have to retype them after rearranging.
Changing how days are labeled
That's a separate setting. Day Title, also under advanced options, controls whether a column reads "Monday", "August 3", or "Monday, August 3, 2026" — see Planbook advanced options for the full list of formats and the day-of-school count option.