update readme with usage

README.md

@@ -1,4 +1,83 @@
 # Web3Kt
 Multiplatform Web3 Library
 
+# Usage
+
+## Solana
+
+### Build a Transaction
+
+```kotlin
+// Solana Memo Program 
+val account = SolanaPublicKey(keyPair.publicKey)
+val memoProgramId = SolanaPublicKey.from("MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr")
+val memoInstruction = TransactionInstruction(
+    memoProgramId,
+    listOf(AccountMeta(account, true, true)),
+    "hello world ".encodeToByteArray()
+)
+
+// Build Message
+val blockhash = Blockhash(getRecentBlockhash())
+val message = Message.Builder()
+    .addInstruction(memoInstruction)
+    .setRecentBlockhash(blockhash)
+    .build()
+```
+
+### Prepare a Signer
+
+using [Diglol Crypto library](https://github.com/diglol/crypto) for ED25519 signing:
+
+```kotlin
+// prepare signer
+val keyPair = Ed25519.generateKeyPair()
+val signer = object : Ed25519Signer() {
+    override val publicKey: ByteArray get() = keyPair.publicKey
+    override suspend fun signPayload(payload: ByteArray): ByteArray = Ed25519.sign(keyPair, payload)
+}
+```
+
+### Sign Message & Build Transaction
+
+```kotlin
+// Sign Message
+val signature = signer.signPayload(message.serialize())
+
+// Build Transaction
+val transaction = Transaction(listOf(signature), message)
+```
+
+### Send Transaction to RPC
+
+Using Base58 encoding from [MultiMult](https://github.com/Funkatronics/multimult) and Solana RPC driver from [RpcCore](https://github.com/Funkatronics/RpcCore)
+
+```kotlin
+// serialize transaction
+val transactionBytes = transaction.serialize()
+val encodedTransaction = Base58.encodeToString(transactionBytes)
+
+// setup RPC driver
+val rpcUrl = "https://api.endpoint.com"
+val rpcDriver = Rpc20Driver(rpcUrl, MyNetworkDriver())
+
+class SendTransactionRequest(encodedTransaction: String, requestId: String)
+    : JsonRpc20Request(
+        method = "sendTransaction",
+        params = buildJsonArray {
+            add(encodedTransaction)
+        },
+        requestId
+    )
+
+// build rpc request
+val requestId = 1
+val rpcRequest = SendTransactionRequest(encodedTransaction, requestId)
+
+// send the request and get response
+// using JsonElement.serializer() will return the JSON RPC response. you can use your own serializer to get back a specific object
+val rpcResponse = rpcDriver.makeRequest(rpcRequest, JsonElement.serializer())
+```
+
+