Add howto guide on sample data download

docs/howto_guides/sample_data.rst

@@ -1,4 +1,43 @@
-.. dkist:howto-guides:sample-data
+.. dkist:howto-guide:sample-data
 
 Downloading the Sample Data with Globus
 =======================================
+
+The Python tools provide a few different partial datasets as sample data, these are used in documentation and examples.
+This how to guide will show you how to download the complete data for these datasets.
+
+
+Searching for and downloading the ASDF file
+-------------------------------------------
+
+Using the `BKPLX <https://dkist.data.nso.edu/datasetview/BKPLX>`__ dataset from the VISP we download the ASDF file and create a `.Dataset` object.
+
+.. code-block:: python
+
+    from sunpy.net import Fido, attrs as a
+
+    import dkist
+    import dkist.net
+
+    results = Fido.search(a.dkist.Dataset("BKPLX"))
+    asdf_file = Fido.fetch(results, ")
+
+    ds = dkist.load_dataset(asdf_file)
+
+
+Downloading the FITS files with Globus
+--------------------------------------
+
+Having loaded the ASDF file into a `.Dataset` we can download the Stokes I profile as so:
+
+.. code-block:: python
+
+    ds[0].files.download()  # doctest: +SKIP
+
+This will download all the FITS files into the same directory as the ASDF file.
+
+To download the whole dataset do:
+
+.. code-block:: python
+
+    ds.files.download()  # doctest: +SKIP