how can I import images in folders into lightroom classic

This is indeed in the Destination options as a dropdown next to 'Organize'. I don't recall the exact wording but one first picks an existing target folder; optionally chooses a new subfolder's name to be made inside that; then the choices for how the imported files are to go inside this destination are:

• all into the one folder;
• as auto dated subfolders (to a chosen scheme);
• as new subfolders to match however the images may be organised within the source.

These three choices are mutually exclusive. The first two options disregard any subfolders present in the source.

For the third option, one would AFAICT, for this use-case, NOT want LrC to disregard camera-made folders.