How do I set a spreadsheet's locale and time zone in Google Sheets?

Steps (computer):

1. Open the spreadsheet in Google Sheets.
2. Click File > Settings.
3. Under General, open the Locale menu and pick your country.
4. Open the Time zone menu and pick your time zone.
5. Click Save settings.

What the locale changes: the file's default currency, date and number formatting, including which character is the decimal separator. For example, a locale can switch dates between month first and day first.

What it does not change: your language in Google Sheets. That is set in your Google Account settings. If your account uses a language other than English, you can show function names in that language by unticking Always use English function names in the same settings box; Sheets supports functions in English and 21 other languages.

Calculation: the Calculation tab sets the calculation mode: Automatic, or Manual, which recalculates only when you click Calculate.

The settings belong to the file, not to each viewer: everyone working on it sees the same locale and time zone, wherever they are.

ProfitDrawer's setup guide notes that if Google shows a different currency after import, you set your symbol on the Settings tab.