docs: Distinguish between coffea-casa and local machine use

analyses/cms-open-data-ttbar/README.md

@@ -22,6 +22,22 @@ This directory is focused on running the CMS Open Data $t\bar{t}$ analysis throu
 
 #### Setting up the environment
 
+##### On Coffea-casa
+
+1. Install [`pixi`](https://pixi.sh/latest/#installation).
+2. From the top level of the entire repository run
+
+```
+pixi run --environment cms-open-data-ttbar install-ipykernel
+```
+
+This will install all of the software and create an `ipkernel` that the Coffea-casa Jupyter Lab instance will be able to see.
+
+3. In the Coffea-casa Jupyter Lab browser, navigate and open up the `analyses/cms-open-data-ttbar/ttbar_analysis_pipeline.ipynb`.
+4. Change the kernel of the notebook to be `cms-open-data-ttbar`.
+
+##### On a local machine
+
 To get a local Python environment that has all the software required for the analysis:
 
 1. Install [`pixi`](https://pixi.sh/latest/#installation) on your machine.
@@ -31,7 +47,8 @@ To get a local Python environment that has all the software required for the ana
 pixi run start
 ```
 
-This will install all of the software and launch a Jupyter lab session. You can then use the file navigator and terminal in Jupyter lab to navigate to this directory to run the analysis.
+This will install all of the software and launch a Jupyter lab session.
+You can then use the file navigator and terminal in Jupyter lab to navigate to this directory to run the analysis.
 
 #### Instructions for paired notebook