diff --git a/codex-plonky2-circuits/README.md b/codex-plonky2-circuits/README.md
index 1058a84..2c951bf 100644
--- a/codex-plonky2-circuits/README.md
+++ b/codex-plonky2-circuits/README.md
@@ -3,5 +3,57 @@ WARNING: This is a work-in-progress prototype, and has not received careful code
 
 This crate is an implementation of the [codex storage proofs circuits](https://github.com/codex-storage/codex-storage-proofs-circuits) for the plonky2 proof system.
 
+## Code organization
+
+- [`capped_tree`](./src/merkle_tree/capped_tree.rs) is an adapted implementation of Merkle tree based on the original plonky2 merkle tree implementation.
+
+- [`capped_tree_circuit`](./src/circuits/capped_tree_circuit.rs) is the circuit implementation for regular merkle tree implementation (non-safe version) based on the above merkle tree implementation.
+
+- [`merkle_safe`](./src/merkle_tree/merkle_safe.rs) is the implementation of "safe" merkle tree used in codex, consistent with the one [here](https://github.com/codex-storage/nim-codex/blob/master/codex/merkletree/merkletree.nim).
+
+- [`safe_tree_circuit`](./src/circuits/safe_tree_circuit.rs) is the Plonky2 Circuit implementation of "safe" merkle tree above.
+
+- [`prove_single_cell`](./src/circuits/prove_single_cell.rs) is the Plonky2 Circuit implementation for proving a single cell in slot merkle tree. 
+
+## Usage
+TODO!
+
 ## Benchmarks
-TODO ...
\ No newline at end of file
+In here we show the preliminary benchmarks of codex storage proofs circuits. 
+
+### Running benchmarks
+To run the benchmarks for safe merkle tree circuit, you can use the following command:
+
+```bash
+cargo bench --bench safe_circuit
+```
+To run the benchmarks for proving cells circuit, you can use the following command:
+Note: make sure to asjust the parameters as need in [`prove_single_cell`](./src/circuits/prove_single_cell.rs)
+
+```bash
+cargo bench --bench safe_circuit
+```
+
+### Results
+Benchmark results for safe Merkle Tree depth 16 with and 5 samples
+
+| Operation | Time (ms)        |
+|-----------|------------------|
+| **Build** | 19.353 ms        |
+| **Prove** | 29.699 ms        |
+| **Verify**| 2.0137 ms        |
+
+Circuit size: 2<sup>9</sup> gates
+Proof size: 103,372 bytes
+
+Benchmark results for proving 5 cells in a Merkle tree with max depth 16 with and 5 samples
+Note: the small tree (block tree) is of depth 5 so 32 cells in each block
+
+| Operation | Time (ms)        |
+|-----------|------------------|
+| **Build** | 17.835 ms        |
+| **Prove** | 28.743 ms        |
+| **Verify**| 1.9792 ms        |
+
+Circuit size: 2<sup>9</sup> gates
+Proof size: 103,372 bytes