Update README and include screenshots

Author: dyng

README.md

@@ -1,14 +1,22 @@
 ## Ramen - A Terminal Interface for Ethereum 🍜
 
-Ramen is a powerful terminal UI to interact with [Ethereum Network](https://ethereum.org/en/). It allows you to observe latest chain status, check account's balance and transaction history, navigate blocks and transactions, view smart contract's source code or call its functions, and many things more!
+Ramen is a good-old terminal UI to interact with [Ethereum Network](https://ethereum.org/en/). It allows you to observe latest chain status, check account's balance and transaction history, navigate blocks and transactions, view smart contract's source code or call its functions, and many things more!
 
-(screenshots here)
+1. View account balance, transactions etc.
+
+    <img src="https://user-images.githubusercontent.com/1492050/215658150-93b09da7-52b2-4366-ba24-4a56668cf2a8.png"/>
+
+2. Call contract's function
+
+    <img src="https://user-images.githubusercontent.com/1492050/215658167-b38bcf0b-8dd4-4b95-8198-5411fe3fd7e0.png"/>
 
 Additionally, Ramen is also well designed for smart contract development. Ramen can connect to a local chain (such as the one provided by Hardhat) to view transaction history of smart contract in development, call functions for testing, or verify its storage. Just works like Etherscan, but for your own chain!
 
 ## Installation
 
-Currently Ramen is under active development and its interface, key-bindings, configurations are subject to change. As a result, you can install Ramen only by building from source at this time.
+**Currently Ramen is under active development and its interface, key-bindings, configurations are subject to change.**
+
+As a result, you can install Ramen only by building from source at this moment.
 
 ### Building From Source
 
@@ -35,7 +43,7 @@ To access Alchemy and Etherscan's service, you need an Api Key respectively. Ple
 - [Alchemy Quickstart Guide](https://docs.alchemy.com/lang-zh/docs/alchemy-quickstart-guide)
 - [Etherscan: Getting an API key](https://docs.etherscan.io/getting-started/viewing-api-usage-statistics)
 
-When the API keys are ready, you can create a configuration file `.ramen.json` in your home directory and place keys there.
+When the API keys are ready, you can create a configuration file `.ramen.json` in your home directory (e.g. `~/.ramen.json`) and place keys there.
 
 ```json
 {
@@ -53,6 +61,17 @@ Then you can launch Ramen now.
 # connect to Goerli Testnet
 ./ramen --network "goerli"
 ```
+
+### Key Bindings
+
+Ramen inherits key bindings from underlying UI framework [tview](https://github.com/rivo/tview), the most frequently used keys are the following:
+
+| Key | Action |
+|---|---|
+|`j`, `k`|Move cursor up and down|
+|`enter`|Select an element|
+|`tab`|Switch focus among elements|
+
 ### Connect Local Network
 
 [Hardhat](https://hardhat.org/) / [Ganache](https://trufflesuite.com/ganache/) provides a local Ethereum network for development purpose. Ramen can be used as an user interface for these local networks.
@@ -61,6 +80,10 @@ Then you can launch Ramen now.
 ./ramen --provider "local"
 ```
 
+## Contribution
+
+Ramen is an open source project, any kind of contribution is welcome! Feel free to open issues for feature request, bug report or discussions.
+
 ## License
 
 Ramen is released under the Apache 2.0 license. See LICENSE for details.