Update README.md

Author: peterzhu2118

README.md

@@ -6,51 +6,14 @@ This repository holds the [MMTk](https://www.mmtk.io/) bindings for Ruby. The bi
 
 ### Building
 
-Since this repository is sync'd into [ruby/ruby](https://github.com/ruby/ruby/), you can choose to either build it in this repository or build it in ruby/ruby. If you're building it in this repository, note that it is only expected to work on the latest commit of Ruby master.
-
-To build `librubygc.mmtk.so` locally, run the following:
-
-```sh
-  rake compile
-```
-This command will:
-
-   - **Clone the Ruby repository**: If you don't already have it, the script clones Ruby into `res/ruby`.
-   - **Copy MMTk GC code**: It copies the MMTk garbage collector code into the Ruby source tree.
-   - **Configure and build Ruby**: Sets up the build configurations to integrate MMTk with Ruby's garbage collector API.
-   - **Compiling the MMTk shared library**: Builds `librubygc.mmtk.so` using Rust's Cargo build system.
-   - **Install the shared library**: Copies `librubygc.mmtk.so` into the `mod_gc` directory.
-
-Once it's done, you'll have a shared object `mod_gc/librubygc.mmtk.so` (`modgc/librubygc.mmtk.bundle` on macOS), that can be loaded into any Ruby interpeter built `--with-shared-gc` support using the path.
-
-Example:
-
-```
-./configure --with-shared-gc=$HOME/mmtk/mod_gc
-```
-
-Successful builds, when loaded, will display `+GC[mmtk]`  in the Ruby version string. This indicates that Ruby has been compiled with shared GC support and that MMTk is loaded.
-
-```sh
-  RUBY_GC_LIBRARY=mmtk ruby -v
-  ruby 3.4.0dev (2024-11-25T13:05:23Z master f127bcb829) +PRISM +GC[mmtk] [arm64-darwin24]
-```
-
-**Note**: Make sure you have all the necessary dependencies installed:
-
-- **Rust toolchain**: Required for building MMTk.
-- **Ruby build dependencies**: Libraries and tools needed to compile Ruby from source.
-- **Rake**: Ruby's build program, used to run the compile task.
-
-That's it! You're all set to experiment with different GC algorithms in Ruby using MMTk.
-
-
-
-
-
-
-
+> [!NOTE]
+> This repository is synchronized into [ruby/ruby](https://github.com/ruby/ruby/), you can choose to either build it in this repository or build it in ruby/ruby. If you're building it in this repository, note that it is only expected to work on the latest commit of Ruby master.
 
+1. Ensure you have the Rust toolchain installed. You can follow [these instructions](https://www.rust-lang.org/tools/install) to install it.
+1. Ensure that you are running with Ruby from the latest commit of Ruby master and your Ruby is configured with `--with-modular-gc`. If you're unsure how to do this, refer to the ["building guide"](https://github.com/ruby/ruby/tree/master/gc#building-guide) for Modular GC.
+1. Run `bundle install`.
+1. Run `bundle exec rake` to compile and install MMTk as a Modular GC.
+1. You can now run Ruby with environment variable `RUBY_GC_LIBRARY=mmtk` to use MMTk.
 
 ### Running
 
@@ -60,7 +23,3 @@ After building Ruby and the MMTk bindings, run Ruby with `RUBY_GC_LIBRARY=mmtk`
 - `MMTK_HEAP_MODE=<fixed|dynamic>`: Configures the MMTk heap used. `fixed` is a fixed size heap, `dynamic` is a dynamic sized heap that will grow and shrink in size based on heuristics using the [MemBalancer](https://dl.acm.org/doi/pdf/10.1145/3563323) algorithm. Defaults to `dynamic`.
 - `MMTK_HEAP_MIN=<size>`: Configures the lower bound in heap memory usage by MMTk. Only valid when `MMTK_HEAP_MODE=dynamic`. `size` is in bytes, but you can also append `KiB`, `MiB`, `GiB` for larger sizes. Defaults to 1MiB.
 - `MMTK_HEAP_MAX=<size>`: Configures the upper bound in heap memory usage by MMTk. Once this limit is reached and no objects can be garbage collected, it will crash with an out-of-memory. `size` is in bytes, but you can also append `KiB`, `MiB`, `GiB` for larger sizes. Defaults to 80% of your system RAM.
-
-## Code structure
-
-TODO