chore: clean up cache docs a bit

docs/usage/cache.md

@@ -1,26 +1,36 @@
 
 ## Objective
 
-## Example
+The weave pipeline utilizes a number of large file resources including containers, reference genomes, reference databases, and indexes. This
+command allows for the user to download all these files serially in one-shot. This execution method will updated to include a parallel cluster
+option for faster execution.
+
+## Execution
+
+### Example command
 
 ```bash title="cache commmand"
 # starting from install
 ./weave cache ./output_directory/
 ```
 
+### Output
+
 > Warning: cache download only implemented in serial local mode currently<br />
 > Getting docker resource bcl2fastq...<br />
-> <singularity output><br />
+> ...singularity output...<br />
 > Getting docker resource weave...<br />
-> <singularity output><br />
+> ...singularity output...<br />
 > Getting web resource kraken...<br />
-> <progress bar><br />
+> ...progress bar...<br />
 > Getting web resource kaiju...<br />
-> <progress bar><br />
+> ...progress bar...<br />
 > Cache downloads complete!<br />
 
 ## Contents
 
+The current contents of what all is downloaded via the cache command are:
+
 1. All pipeline containerized images in read-only Singularity Image Format (SIF)
 2. Kraken2 kmer databases
 3. Kaiju kmer databases