MMDF: Add tip for certificate importing

Serverless-for-Iran/README.md

@@ -23,3 +23,26 @@ Same as "Serverless for Iran" but use "DoH h2c + domain fronting" for DNS and Mi
 **Requires a self-signed-certificate: You can create it using "./xray tls cert -ca -file=mycert" command.**
 
 **Also, the certificate must be imported into "Trusted-Root-Certification-Authorities" of system/browser.**
+
+## How to import the certificate into the system/browser:
+
+**Windows**:
+  
+  * System:
+    
+    Right click on the certificate -> Install certificate -> Local machine -> Place all certificates in the following store -> Select "Trusted Root Certification Authorities"
+    
+  * Browser(Chrome):
+    
+    Settings -> Privacy and security -> Security -> Manage certificates -> Manage imported certificates from Windows -> Trusted Root Certification Authorities -> Import -> Select the certificate file -> Place all certificates in the following store -> Select "Trusted Root Certification Authorities"
+
+**Android**:
+
+  * Chromium based browsers and Apps that support user-certificates:
+
+    Setting -> Security and privacy -> More security settings -> Install from device storage -> CA Certificate -> Install anyway -> Select the Certificate file on your storage.
+
+  * Firefox:
+
+    Run the firefox browser -> Settings -> About Firefox -> Tap the Firefox logo five times -> Navigate to Settings -> Secret Settings -> Toggle "Use third party CA certificates"
+