Armbian config is the utility you will use to change personal settings. It is available under Settings in the Applications menu. It will first ask you to enter your password then show you the main page.

Select Personal.

Timezone:
Keeping your timezone set properly is important as otherwise you may find that browsers don't work.
First select the geographic area you are in, then select a city you know is in your current timezone.
Language:
You can change the default language to use by selecting Locales. First it will show you which Locales have already been generated. The format is a two-letter code for the language (for example, en for English, es for Spanish) followed by a two letter geographic code (usually country) and ending in ".UTF-8 UTF-8". So to add US Spanish, select es_US.UTF-8 UTF-8. Then select "OK" to go to the next screen.
This shows what is the selected default language to use. Highlight the one you'd like and again, select "OK".
Keyboard:
Select Keyboard and then select your keyboard model from the list. If it is not shown, select one of the "Generic..." keyboards that closest matches yours. Select "OK".
Next you pick the layout for your keyboard from a list shown. When done, click "OK".
The last few screens let you modify special keys. Usually hit Enter for these options.