update installation and usage instructions

Author: rzitomer

README.md

@@ -22,7 +22,22 @@ Motivation behind this project: http://third-bit.com/2017/09/30/git-graphs-and-e
 - [Blog](https://ubc-mds.github.io/RStudio-GitHub-Analysis/)
 
 ## Usage
-PLACEHOLDER 
+Run the following commands to reproduce this analysis:
+```{bash}
+snakemake get_ght_data # Downloads GH Torrent data from figshare. Be aware that the file is quite large, and downloading can take 1-2 hours.
+
+snakemake run_analysis # Run our pipeline; generate embeddings, clusters, tsne graph, motif report, etc.
+
+snakemake generate_images # Generate images of our most important findings.
+```
+
+To change parameters from the command line, simply put `--config param=value` after your snakemake call. For a full list of configurable parameters, see the `config.json` file in the root directory of this project. 
+For example, if you wanted to run the analysis with 5 workers instead of the default, run:
+
+```{bash}
+snakemake run_analysis --config n_workers=5
+```
+ 
 
 ### Example
 From the root directory, run: 
@@ -32,10 +47,10 @@ python src/python src/github_analysis/main.py -dp "/home/rayce/Assignments/Capst
 ```
 
 ## Installation instructions
-To get credentials file for GitHub Torrent Google Cloud (necessary for re-running the pipeline to generate images):
+First, to get credentials file neccessary for pulling the GitHub Torrent from Google Cloud (necessary for re-generating images for our analysis):
 
-- Follow the instructions here to create and download a credentials file: https://developers.google.com/adwords/api/docs/guides/authentication#generate_oauth2_credentials
-- Change the name of the file to `credentials_file.json` and put it in the root directory of the project (a sample file with the same name is included as a reference).
+- Follow the instructions under 'Set up a service account' to create and download a credentials file: https://cloud.google.com/video-intelligence/docs/common/auth
+- Change the name of the file to `credentials_file.json` and put it in the root directory of the project (a sample file with the name `credentials_file_EXAMPLE.json` is included as a reference).
 
 
 ## Data Repository