See here for more information:
http://manual.ninoxdb.de/en/import-attachments/

I have a file saved as .csv from Numbers, but can not seem to get it to import. Not sure what directions mean by "Open the file you want to import inside another app (e.g. Mail) with Ninox. " I do not see any way to open file inside Numbers so Ninox can see it.

Try this:
- Open Ninox.
- Create a new (empty) database
- Switch to Admin Mode (wrench icon in to right corner is red).
- Select "Import Data".

Birger - Ninox Support

Thanks. What you suggested works. However, I was trying to import data into (actually amend data to) an existing table and it appears that option is not available.

To import into an existing table try this:
- Open the table you want to import into.
- Select "Import data..." from the gear menu.
- Follow the assistant to assign the csv columns to the Ninox fields.

Birger - Ninox Support

Importing a csv and cant get dates to work properly date was DD/MM/YYYY in sheet, totally screwed up when import into Ninox.. Flipped it in the sheet program to DD/YYYY/MM slightly better the Day and Year are now correct, however the month is always showing Jan? Sorry if this has been resolved elsewhere ... couldn't find it... Newbie with Ninox..

Please make sure to check the import options to see if there is a suitable date format:

Birger - Ninox Support

In your example, Gender seems to be a dropdown field.
How do you import those? I tried the text and I tried the number and both don't seem to work.

Also, how can you import YES/NO fields?

0 and n and no and... are considered "No" - Everything else is "Yes".

Birger - Ninox Support