diff --git a/src/main/kotlin/net/revanced/patcher/cache/PatchData.kt b/src/main/kotlin/net/revanced/patcher/cache/PatchData.kt
index 68efce8..5cc2c16 100644
--- a/src/main/kotlin/net/revanced/patcher/cache/PatchData.kt
+++ b/src/main/kotlin/net/revanced/patcher/cache/PatchData.kt
@@ -6,7 +6,7 @@ import org.objectweb.asm.tree.MethodNode
 data class PatchData(
     val cls: ClassNode,
     val method: MethodNode,
-    val sr: ScanData
+    val sd: ScanData
 )
 
 data class ScanData(
diff --git a/src/main/kotlin/net/revanced/patcher/writer/ASMWriter.kt b/src/main/kotlin/net/revanced/patcher/writer/ASMWriter.kt
index 1d4675c..5165cf6 100644
--- a/src/main/kotlin/net/revanced/patcher/writer/ASMWriter.kt
+++ b/src/main/kotlin/net/revanced/patcher/writer/ASMWriter.kt
@@ -1,9 +1,10 @@
 package net.revanced.patcher.writer
 
+import org.objectweb.asm.tree.AbstractInsnNode
 import org.objectweb.asm.tree.InsnList
 
 object ASMWriter {
-    fun InsnList.testingWow() {
-
+    fun InsnList.setAt(index: Int, node: AbstractInsnNode) {
+        this[this.get(index)] = node
     }
 }
\ No newline at end of file
diff --git a/src/test/kotlin/net/revanced/patcher/PatcherTest.kt b/src/test/kotlin/net/revanced/patcher/PatcherTest.kt
index a6fc121..9f09336 100644
--- a/src/test/kotlin/net/revanced/patcher/PatcherTest.kt
+++ b/src/test/kotlin/net/revanced/patcher/PatcherTest.kt
@@ -4,9 +4,11 @@ import net.revanced.patcher.patch.Patch
 import net.revanced.patcher.patch.PatchResultSuccess
 import net.revanced.patcher.signature.Signature
 import net.revanced.patcher.util.ExtraTypes
+import net.revanced.patcher.writer.ASMWriter.setAt
 import org.junit.jupiter.api.Test
 import org.objectweb.asm.Opcodes.*
 import org.objectweb.asm.Type
+import org.objectweb.asm.tree.LdcInsnNode
 
 internal class PatcherTest {
     private val testSigs: Array<Signature> = arrayOf(
@@ -40,9 +42,19 @@ internal class PatcherTest {
 
         patcher.addPatches(
             Patch ("TestPatch") {
+                // Get the method from the resolver cache
                 val main = patcher.cache.methods["mainMethod"]
+                // Get the instruction list
                 val insn = main.method.instructions!!
-
+                // Let's modify it, so it prints "Hello, ReVanced!"
+                // Get the start index of our signature
+                // This will be the index of the LDC instruction
+                val startIndex = main.sd.startIndex
+                insn.setAt(startIndex, LdcInsnNode("Hello, ReVanced!"))
+                // Finally, tell the patcher that this patch was a success.
+                // You can also return PatchResultError with a message.
+                // If an exception is thrown inside this function,
+                // a PatchResultError will be returned with the error message.
                 PatchResultSuccess()
             }
         )