Custom Model Not Compiling (Again)

Hello, so I made a 1 arm zombie model with blockbench and exported it to mcreator. Set my mob to the model, saved and my mob caused an error. this is what appears in the console:

Executing Gradle task: build

Build info: MCreator 2020.2.14217, 1.12.2, 64-bit, 4096 MB, Mac OS X, JVM 1.8.0_232, JAVA_HOME: /Users/abbifrisbie/Desktop/MCreator.app/Contents/MacOS/jdk/Contents/Home/jre

This mapping 'snapshot_20171003' was designed for MC 1.12! Use at your own peril.

:deobfCompileDummyTask

:deobfProvidedDummyTask

:sourceApiJava UP-TO-DATE

:compileApiJava NO-SOURCE

:processApiResources NO-SOURCE

:apiClasses UP-TO-DATE

:sourceMainJava UP-TO-DATE

/Users/abbifrisbie/MCreatorWorkspaces/zombieapocolypse/build/sources/main/java/net/mcreator/zombieapocolypse/entity/EntityOnearmzombie.java:141: error: cannot find symbol 
    
   public static class Modelsteve extends EntityModel<Entity> {

                                          ^

  symbol:   class EntityModel

  location: class EntityOnearmzombie

/Users/abbifrisbie/MCreatorWorkspaces/zombieapocolypse/build/sources/main/java/net/mcreator/zombieapocolypse/entity/EntityOnearmzombie.java:181: error: cannot find symbol 
    
      public void render(MatrixStack matrixStack, IVertexBuilder buffer, int packedLight, int packedOverlay, float red, float green, float blue,

                         ^

  symbol:   class MatrixStack

  location: class Modelsteve

/Users/abbifrisbie/MCreatorWorkspaces/zombieapocolypse/build/sources/main/java/net/mcreator/zombieapocolypse/entity/EntityOnearmzombie.java:181: error: cannot find symbol 
    
      public void render(MatrixStack matrixStack, IVertexBuilder buffer, int packedLight, int packedOverlay, float red, float green, float blue,

                                                  ^

  symbol:   class IVertexBuilder

  location: class Modelsteve

3 errors

:compileJava FAILED

FAILURE: Build failed with an exception.

* What went wrong:

Execution failed for task ':compileJava'.

> Compilation failed; see the compiler error output for details.

* Try:

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 2s

5 actionable tasks: 3 executed, 2 up-to-date

BUILD FAILED

Task completed in 7299 milliseconds

any help?