Update README

README.md

@@ -6,7 +6,11 @@
 
 [![Continuous Integration - proof verification tests](https://github.com/HerodotusDev/cairo-verifier/actions/workflows/proof_verification_tests.yml/badge.svg)](https://github.com/HerodotusDev/cairo-verifier/actions/workflows/proof_verification_tests.yml)
 
-## Building the Verifier
+## Using Verifier contracts
+
+To use the Verifier for verifying proofs on starknet, you need to generate calldata for your proof. The easiest way to do that is to use [Calldata Generator](https://github.com/HerodotusDev/integrity-calldata-generator). It also provides script for automatic transaction sending (proof verification is split into multiple transactions, for more information see [Split Verifier Architecture](/README.md#split-verifier-architecture)).
+
+## Running locally
 
 To build the Cairo Verifier, follow these steps:
 
@@ -24,9 +28,7 @@ If you want to build for other layouts, refer to [Configure Verifier](/README.md
 scarb test
 ```
 
-## Running the Verifier on Example Proof
-
-### Local Proof Verification
+### Running the Verifier on Example Proof
 
 For local proof verification, follow these steps:
 
@@ -37,7 +39,7 @@ cargo run --release --bin runner -- --program target/dev/cairo_verifier.sierra.j
 cargo run --release --bin runner -- --program target/dev/cairo_verifier.sierra.json -c cairo1 < examples/proofs/recursive/cairo1_example_proof.json
 ```
 
-### Starknet Proof Verification
+<!-- ### Starknet Proof Verification
 
 To verify proofs on Starknet, proceed with the following steps:
 
@@ -54,9 +56,9 @@ cd examples/starknet
 ./1-verify-proof.sh 0x274d8165a19590bdeaa94d1dd427e2034462d7611754ab3e15714a908c60df7 calldata
 ```
 
-[List of deployed Verifier Contracts](deployed_contracts.md)
+[List of deployed Verifier Contracts](deployed_contracts.md) -->
 
-## Configure Verifier
+### Configure Verifier
 
 By default, the verifier is configured for monolith version, recursive layout and keccak hash for verifier unfriendly commitment layers. You can easily change that by using scarb's features:
 
@@ -68,7 +70,7 @@ layout types: [dex, recursive, recursive_with_poseidon, small, starknet, starkne
 hash types: [keccak, blake2s]
 verifier types: [monolith, split]
 
-## Benchmarking
+### Benchmarking
 
 In order to launch benchmarking, just run this (it requires recursive layout configuration):
 
@@ -85,3 +87,15 @@ For detailed instructions and examples, refer to the Stone Prover [documentation
 How to prove [Cairo0](https://github.com/starkware-libs/stone-prover?tab=readme-ov-file#creating-and-verifying-a-proof-of-a-cairozero-program) program with Stone Prover.
 
 How to prove [Cairo1](https://github.com/starkware-libs/stone-prover?tab=readme-ov-file#creating-and-verifying-a-proof-of-a-cairo-program) program with Stone Prover.
+
+## Split Verifier Architecture
+
+### Background information
+
+TODO: why we need splitting, starknet limits, autogenerated and fri split
+
+### FactRegistry and Proxy contract
+
+Since verifier can be configured in many ways and some parts of the logic changes with new stone versions, a contract which routes calls to the correct verifier is needed. This task is handled by FactRegistry contract that also stores data for all verified proofs.
+
+FactRegistry contract is trustless which means that owner of the contract can't override or change any existing behavior, they can only add new verifiers. Proxy contract on the other hand is upgradable, so every function can be changed or removed. It has the advantage of having all future updates of the verifier logic without having to replace the address of FactRegistry contract.