diff --git a/README.md b/README.md
index ec09f30..db26029 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,21 @@
-## TETRA_CRYPTO
+# TETRA_CRYPTO
 
 Implementation of TEA-1 and TEA-3 in rust.  
 Based on "Observations on TETRA Encryption Algorithm TEA-3", "ETSI TS 104 053-1, TETRA Air Interface Security, Algorithms Specifications" and [Midnight Blue's C code](https://github.com/MidnightBlueLabs/TETRA_crypto)
+
+## tests and build
+
+```bash
+cargo test
+cargo build --release
+```
+
+## commands
+
+| Command          | Description                                              |
+|------------------|----------------------------------------------------------|
+| lfsr             | Test the LFSR                                            |
+| tea1             | Test TEA-1 attack                                        |
+| tea3             | Test TEA-3 keystream and encryption/decryption           |
+| periods          | Test for periods in TEA-3 register h                     |
+| greatest-period  | Search for greatest period in TEA-3 register h           |