Phrase and Pronoun Agreement Errors

https://github.com/AppFlowy-IO/AppFlowy-Docs/blob/cb1d8a02d240749c85bb75e37c96b9903393f235/essential-documentation/contribute-to-appflowy/write-for-appflowy/drafts/draft-how-to-add-a-new-property-to-appflowy-database.md?plain=1#L15

### Incorrect Phrase (Singular vs. Plural):
***Inaccurate:***
"behind the `scene`"
***Accurate:***
"behind the `scenes`"

### Clarity (Optional Improvement for Smoothness):
***Inaccurate:***
"to model the data and work with `them`"
***Accurate:***
"to model the data and work with `it`"
Since "data" is often treated as uncountable in modern usage, so "it" fits better here. If treating "data" as plural, "them" is acceptable but less common.