update README with new scripts

04_Age_Expansion_Analysis/README.md

@@ -1,6 +1,5 @@
 # Aging and Expansion Analyses
 
-These scripts are separated into 2 parts: first creating the aging and expansion data and then secondly running the various comparisons presented in the manuscript.
+These scripts are separated into 3 parts: first creating the aging and expansion data, then secondly creating the matched samples and running the whole brain regression analyses, and finally running the various comparisons between aging and expansion presented in the manuscript.
 
 All the results from these analyses for the manuscript are availble to download [here](https://zenodo.org/records/10141986).
-