diff --git a/Makefile b/Makefile
index 2bfc0a7..965b5c2 100644
--- a/Makefile
+++ b/Makefile
@@ -9,6 +9,9 @@ install: clean
 	foundryup
 	forge install
 
+tx:
+	npx create-safe-tx
+
 hash:
 	forge script script/HashData.s.sol
 
diff --git a/README.md b/README.md
index c3685be..67d66a9 100644
--- a/README.md
+++ b/README.md
@@ -6,15 +6,18 @@
 - Run `make` to initialize the repository.
 - Create a `.env` file from the template [`.env.example`](./.env.example) file.
   - Use the environment variable `SAFE_NONCE` to override a transaction's nonce. Leave it blank to use the default, latest Safe nonce.
+  - Use the environment variable `FOUNDRY_ETH_RPC_URL` to customize the RPC endpoint used. This is useful to interact with a Safe deployed on another chain than Ethereum mainnet (the default one).
 
-You can customize the RPC url used in [`foundry.tml`](./foundry.toml) under the `rpc_endpoint` section. This is useful if your Safe is not deployed on mainnet (which is the default chain used).
+### Build a Safe tx
+
+- Run `make tx` and follow the steps to create a Safe transaction using [create-safe-tx](https://github.com/morpho-labs/create-safe-tx); OR
+- Put the transaction's raw data in `data/tx.json`
 
 ### Sign a Safe tx
 
-1. Put the transaction's raw data in `data/tx.json`
-2. Hash the transaction's raw data: `make hash`
-3. To sign the data with a Ledger, run: `make sign:ledger`
-4. Share the content of `data/signatures.txt` with the signer who will execute the transaction on the Safe
+1. Hash the transaction's raw data: `make hash`
+2. To sign the data with a Ledger, run: `make sign:ledger`
+3. Share the content of `data/signatures.txt` with the signer who will execute the transaction on the Safe
 
 ### Batch signatures and execute transaction
 
@@ -26,6 +29,7 @@ You can customize the RPC url used in [`foundry.tml`](./foundry.toml) under the
 ### Wallet support
 
 With `make sign` & `make exec`, one can also use any other wallet provider available with `cast`:
+
 - `make cmd:interactive` to input the private key to the command prompt
 - `make cmd:ledger` to use a Ledger
 - `make cmd:trezor` to use a Trezor
@@ -36,14 +40,14 @@ With `make sign` & `make exec`, one can also use any other wallet provider avail
 
 ```json
 {
-    "to": "0x0000000000000000000000000000000000000000",
-    "value": 0,
-    "data": "0x", // The raw tx data
-    "operation": 0, // 0 for a call, 1 for a delegatecall
-    "safeTxGas": 0,
-    "baseGas": 0,
-    "gasPrice": 0,
-    "gasToken": "0x0000000000000000000000000000000000000000", // Indicates the tx will consume the chain's default gas token (ETH on mainnet)
-    "refundReceiver": "0x0000000000000000000000000000000000000000" // Indicates the tx's refund receiver will be the address executing the tx
+  "to": "0x0000000000000000000000000000000000000000",
+  "value": "0", // The tx value (in ETH), must be a string
+  "data": "0x", // The raw tx data, must start with 0x
+  "operation": 0, // 0 for a call, 1 for a delegatecall
+  "safeTxGas": 0,
+  "baseGas": 0,
+  "gasPrice": 0,
+  "gasToken": "0x0000000000000000000000000000000000000000", // Indicates the tx will consume the chain's default gas token (ETH on mainnet)
+  "refundReceiver": "0x0000000000000000000000000000000000000000" // Indicates the tx's refund receiver will be the address executing the tx
 }
 ```
diff --git a/data/template.json b/data/template.json
index 644870c..4797d61 100644
--- a/data/template.json
+++ b/data/template.json
@@ -1,6 +1,6 @@
 {
     "to": "0x0000000000000000000000000000000000000000",
-    "value": 0,
+    "value": "0",
     "data": "0x",
     "operation": 0,
     "safeTxGas": 0,
diff --git a/script/SafeTxDataBuilder.sol b/script/SafeTxDataBuilder.sol
index c1ba5fb..5d5d283 100644
--- a/script/SafeTxDataBuilder.sol
+++ b/script/SafeTxDataBuilder.sol
@@ -54,7 +54,7 @@ contract SafeTxDataBuilder is Script, SignatureDecoder {
         string memory json = vm.readFile(TX_FILE);
 
         txData.to = json.readAddress("$.to");
-        txData.value = json.readUint("$.value");
+        txData.value = json.readUint("$.value"); // TODO: this is actually a string. Check if it works properly
         txData.data = json.readBytes("$.data");
         txData.operation = Enum.Operation(json.readUint("$.operation"));
         txData.safeTxGas = json.readUint("$.safeTxGas");