docs: add pre-auth readme

packages/dapp-toolkit/README.md

@@ -45,14 +45,6 @@ Use our [CLI tool](https://github.com/radixdlt/create-radix-dapp) to scaffold a
 npx create-radix-dapp@latest
 ```
 
-## Using `create-radix-dapp`
-
-You can easily start experimenting with Radix dApp Toolkit and various frameworks by using our [CLI tool](https://github.com/radixdlt/create-radix-dapp) to scaffold a new project. Just paste following command into your terminal and it will walk you through all required steps!
-
-```bash
-npx create-radix-dapp@latest
-```
-
 # Usage
 
 ## Getting started
@@ -492,6 +484,28 @@ const transactionIntentHash = result.value.transactionIntentHash
 
 </details>
 
+## Preauthorization Requests
+
+It is very similar to a transaction request, but it describes only a part of a final transaction – specifically the part that the user cares about, such as a swap they wish to perform within certain acceptable bounds. The pre-authorization is signed and returned to the dApp, which can then include it in a full transaction. A time bound is put on the pre-authorization, so the user knows for how long their pre-authorization is usable.
+
+Creation of preauthorization request object is abstracted away into `SubintentRequestBuilder`. You can set exipration date in two modes:
+- delay in **seconds after preauthorization is signed** by using `.setExpiration('afterDelay', 3600)`
+- provided **exact unix timestamp** to function call `.setExpiration('atTime', 1234567890)`
+
+**Example:**
+```typescript
+ const result = await dAppToolkit.walletApi.sendPreAuthorizationRequest(
+    SubintentRequestBuilder()
+      .manifest(subintentManifest)
+      .setExpiration(
+        'afterDelay',
+        3600,
+      )
+      // .addBlobs('blob1', 'blob2')
+      .message('This is a message')
+  )
+```
+
 # ROLA (Radix Off-Ledger Authentication)
 
 ROLA is method of authenticating something claimed by the user connected to your dApp with the Radix Wallet. It uses the capabilities of the Radix Network to make this possible in a way that is decentralized and flexible for the user.