README: Add info about what this is

README.md

@@ -1,2 +1,74 @@
 # solana-program-rosetta
+
 Multiple implementations of Solana programs across languages
+
+More programs will be added over time!
+
+## Getting started
+
+### Prerequisite for all languages
+
+* Install Rust: https://www.rust-lang.org/tools/install
+
+### Rust
+
+* Install Solana tools
+
+```console
+./install-solana.sh
+```
+
+* Go to a program directory
+
+```console
+cd helloworld
+```
+
+* Build a program
+
+```console
+cargo build-sbf
+```
+
+* Test a program
+
+```console
+cargo test-sbf
+```
+
+### Zig
+
+* Get the compiler
+
+```console
+./install-solana-zig.sh
+```
+
+* Go to the Zig implementation of a program
+
+```console
+cd helloworld/zig
+```
+
+* Build the program
+
+```console
+../../solana-zig/zig build
+```
+
+* Test it
+
+```console
+cd ..
+SBF_OUT_DIR="./zig/zig-out/lib" cargo test"
+```
+
+* OR use the helper from the root of this repo to build and test
+
+```console
+./test-zig helloworld
+```
+
+## Current Programs
+
+* Helloworld: logs a static string using the `sol_log_` syscall