diff --git a/README.md b/README.md
index 213be36..01bfd1d 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,39 @@
 # Tricky Store
 
 A trick of keystore.
+
+## Usage
+
+1. Flash this module and reboot.  
+2. Put keybox.xml to /data/adb/tricky_store/keybox.xml .  
+3. Put target packages to /data/adb/tricky_store/target.txt (Optional).  
+4. Enjoy!  
+
+## keybox.xml
+
+format:
+
+```xml
+<?xml version="1.0"?>
+<AndroidAttestation>
+    <NumberOfKeyboxes>1</NumberOfKeyboxes>
+    <Keybox DeviceID="...">
+        <Key algorithm="ecdsa|rsa">
+            <PrivateKey format="pem">
+-----BEGIN EC PRIVATE KEY-----
+...
+-----END EC PRIVATE KEY-----
+            </PrivateKey>
+            <CertificateChain>
+                <NumberOfCertificates>...</NumberOfCertificates>
+                    <Certificate format="pem">
+-----BEGIN CERTIFICATE-----
+...
+-----END CERTIFICATE-----
+                    </Certificate>
+                ... more certificates
+            </CertificateChain>
+        </Key>...
+    </Keybox>
+</AndroidAttestation>
+```