I want to import data from a spreadsheet into the base, but why is the data displayed in red in the import window?

When you import data from a spreadsheet into EDT, the data appears in red: you must then match the data for each column, replacing Field Ignored with the appropriate field type.
If some data remains in red at the end of the matching process, it's because it doesn't match the expected format: move the cursor over it to find out why.