Update readme

Author: pgherveou

README.md

@@ -2,8 +2,19 @@
 
 A cargo subcommand to build Rust contracts to PolkaVM bytecode.
 
+This tool scaffolds Rust contract projects from Solidity interface files (`.sol`). It automates:
+- Function selector generation
+- Input/output encoding and decoding (ABI)
+
 This tool is designed for building smart contracts in Rust using the low-level API provided by [pallet-revive-uapi](https://docs.rs/pallet-revive-uapi/latest/pallet_revive_uapi/). For a more high-level, user-friendly API, see [Ink!](https://use.ink/).
 
+## Contract Generation
+
+Contracts can be generated using two approaches:
+
+- **High-level API**: Uses the `sol!` macro with automatic struct generation for type-safe contract development
+- **Low-level API**: Provides more manual control over the contract implementation
+
 To learn more, visit the [Rust Contract Template](https://github.com/paritytech/rust-contract-template).
 
 ## Installation