Update README.md

README.md

@@ -38,10 +38,17 @@ from a series of dicom files (each containing 2D image)
 >>> from dicom_csv import join_tree, order_series, stack_images
 >>> from pydicom import dcmread
 >>> from pathlib import Path
+>>>
+>>> # 1. Collect metadata from all dicom files
 >>> folder = Path('/path/to/folder/')
 >>> meta = join_tree(folder, verbose=2)
->>> uid = '...' # unique identifier of a series, you could list them by `meta.SeriesInstanceUID.unique()`
+>>>
+>>> # 2. Select series to load
+>>> uid = '...' # unique identifier of a series you want to load,
+>>>             # you could list them by `meta.SeriesInstanceUID.unique()`
 >>> series = meta.query("SeriesInstanceUID==@uid")
+>>>
+>>> # 3. Read files & combine them into a single volume
 >>> images2d = [dcmread(folder / row[1].PathToFolder / row[1].FileName) for row in series.iterrows()] 
 >>> image3d = stack_images(order_series(images2d))
 ```