Update README.md

README.md

@@ -11,7 +11,9 @@ tags:
 
 This repo contains the datasets used in the [ASAP-Polaris-OpenADMET challenge](https://polarishub.io/blog/antiviral-competition), comprising Potency, ADMET and crystallography data from [ASAP Discovery's](https://asapdiscovery.org/) SARS-CoV-2 / MERS-CoV main protease inhibitor program. 
 
-More detail on the competition and its design can be found at the [relevant preprint](https://chemrxiv.org/engage/chemrxiv/article-details/695db4c1900d745c43b8ec3e)
+More detail on the competition and its design can be found at the [relevant preprint](https://chemrxiv.org/engage/chemrxiv/article-details/695db4c1900d745c43b8ec3e). 
+
+Data is assigned to a train or test split based on criteria laid out in the above preprint. For the tabular data (Potency and ADME) this is indicated in the `Set` column. For structural data split is indicated with the prefix `Train` or `Test`.
 
 ## Experimental data collection