diff --git a/README.md b/README.md
index 4c884d8..985e8e1 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,50 @@
-# DataCon24
\ No newline at end of file
+# DataCon 3.0
+
+Data description:
+
+1. Mixed CPPs.
+Contains CPPs with natural or modified amino acids.
+
+  1.1. POSEIDON
+  Contains heterogeneous experimental data regarding CPP (natural and non-natural amino acids) activity measurements (.csv format), which are:
+  1) peptide name,
+  2) target cell line CPP was tested on cell penetration ability,
+  3) delivered molecule/protein,
+  4) paper PubMed ID,
+  5) cellular uptake measurement + measurement units,
+  6) CPP+cargo concentration,
+  7) incubation time,
+  8) incubation temperature,
+  9) determination method,
+  10) uptake type,
+  11) sequence
+
+2. Natural CPPs.
+Contains only sequences with natural amino acids.
+
+   2.1. CPPBase
+   Contains sequences of CPPs with experimentally proved activity in .fasta format.
+
+   2.2. Experimental and Experimental2
+   Contain more sequences of CPPs with experimentally proved activity in .txt format.
+
+   2.3. Experimental_high_uptake
+   Contain CPP sequences with high (but not stated) uptake in .txt format.
+
+3. Non-CPPs.
+Contains negative CPP samples in .txt format.
+
+   3.1. Generated
+   Contains randomly generated sequences treated as negative.
+
+   3.2. Experimental
+   Contains non-CPP sequences shown not to demonstrate activity experimentally.
+
+4. Non-Natural CPPs.
+Contains CPPs consisting of non-natural amino acids.
+
+   4.1. CPPBase_modified
+   Contains a list of modified CPPs with experimentally proved activity in .fasta format.
+   
+   4.2. CPPBase_modified_symbols
+   Contains a list of abbreviations for modified amino acids  in .txt format (ABBREVIATION: NAME; ...: ...).