What's the difference between checking "Resample Image" and NOT checking "Resample Image" ??
If you check the resample image you change the pixel dimensions of the image. When you resize the image you don't need to do that. for example the scan is 8000 px X12,000 px. That translates to a 8000/300 = ~26 inch print. So at 300 dpi you can make a 26 X39" print, which is fairly large. Resizing just changes the size of the image that photoshop will print.
If you want to change the actual pixel dimension, then you resample. Before you do that, make sure you are working from a duplicate. In your example you would resample the image to 3300 px for an 11X14 inch print @300dpi.
One thing you want to ensure is the maintain proportions box is checkd ( unless you want a distorted image)