To show how to inlcude the library module in app.module.ts

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';
import { RatifyModule } from 'ratify'; // <-- import the RatifyModule from ratify library we built

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    RatifyModule // <-- Import the module to use the exported component from the module
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }