Add initial smart wallets guide (#178)

Author: adam-maj

README.md

@@ -140,7 +140,7 @@ yarn dev:infra
 
 ## User Guide
 
-View all end-points details (Open API Specification) : [User Guide](./docs/UserGuide.md)
+View all end-points details (Open API Specification) : [User Guide](./docs/1-user-guide.md)
 
 ## API Documentation
 

docs/UserGuide.md renamed to docs/1-user-guide.md

@@ -0,0 +1,53 @@
+## Smart Wallets
+
+You can use engine to deploy, manage, and transact with smart wallets on behalf of your users.
+
+Make sure to read the `README.md` and previous `user-guide.md` before starting this one.
+
+### 1. Deploy an account factory
+
+In order to deploy smart wallet accounts (which we'll refer to as "accounts" from here on), you'll need an `AccountFactory` contract deployed. This contract handles deploying individual `Account` contracts for your users.
+
+**Endpoint:** `POST - /deploy/{chain}/deployer.thirdweb.eth/AccountFactory`
+
+**Payload:**
+
+```json
+{
+  "constructorParams": ["0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789"]
+}
+```
+
+### 2. Deploy accounts for your users
+
+Once you have a factory setup, you can use it to deploy accounts for your users.
+
+**Endpoint:** `POST - /contract/{chain}/{account_factory_address}/account-factory/create-account`
+
+```json
+{
+  "admin_address": "0x..." // The user wallet address that you want to deploy a smart wallet for
+}
+```
+
+This will add the `admin_address` as the primary admin that can act on behalf of the newly deployed account.
+
+If you want to control the account with one of your backend wallets, you can specify the backend wallet in the `admin_address` field.
+
+### 3. Grant permissions and sessions
+
+You can manage the permissions of who has control over a smart wallet.
+
+You can grant & revoke admins on your account with the `/contract/{chain}/{account_address}/account/admins` endpoints.
+
+You can grant & revoke sessions on your account which allow specific wallets to interact with specified contracts for a given period of time with the `/contract/{chain}/{account_address}/account/sessions` endpoints.
+
+### 4. Transact with an account
+
+You can make write calls with a smart account by calling any of the write endpoints and specifying both the `x-backend-wallet-address` and `x-account-address` headers.
+
+The `x-backend-wallet-address` should be set to the engine backend wallet that is an admin over the account.
+
+The `x-account-address` should be set to the deployed account address itself.
+
+Write calls made using these headers will initiate a `UserOperation` sent from the specified account.