Here is the example on how to create your own page and add it to the left side menu and breadcrumbs.

1. Create a custom Page

Run this Angular CLI command for generate new component:

ng generate component views/pages/my-page

The result of the command is:

2. Register new component in the theme routing

Register new component in the /src/app/views/themes/default/pages-routing.module.ts file:

// Other imports
import { MyPageComponent } from './../../pages/my-page/my-page.component'; // <= Import component

const routes: Routes = [
  {
    path: '',
    component: PagesComponent,
      canActivate: [NgxPermissionsGuard],
      data: {
        permissions: {
          only: ['ADMIN', 'USER'],
            except: ['GUEST'],
            redirectTo: '/login'
          }
        },
        children: [
        {
          path: '',
          loadChildren: 'app/views/pages/dashboard/dashboard.module#DashboardModule'
        },
        {
          path: 'my-page', // <= Page URL
          component: MyPageComponent // <= Page component registration
        },
        {
          path: 'mail',
          loadChildren: 'app/views/pages/apps/mail/mail.module#MailModule'
        },
        {
          path: 'ecommerce',
          loadChildren: 'app/views/pages/apps/e-commerce/e-commerce.module#ECommerceModule'
        }

// Other code

3. Add page to the left menu

Add page to the left menu in /src/app/core/_config/default/menu.config.ts file:

// Other imports 
export class MenuConfig {
  public config: any = {};

  constructor() {
    this.config = {
      header: {
        self: {},
        items: [
          // Header menu configuration
        ]
      },
      aside: {
        self: {},
        items: [
          {
            title: 'Dashboard',
            desc: 'Some description goes here',
            root: true,
            icon: 'flaticon-line-graph',
            page: '/',
            badge: {type: 'kt-badge--danger', value: '2'},
            translate: 'MENU.DASHBOARD'
          },
          {
            title: 'My Page', // <= Title of the page
            desc: 'Some my description goes here', // <= Description of the page
            root: true,
            page: 'my-page', // <= URL
            icon: 'flaticon-line-graph' // <= Choose the icon
           },
           {section: 'Components'},

// Other code

4. Add page to the breadcumbs

Add page to the breadcrumbs in /src/app/core/_config/default/pages.congif.ts file:

export class PagesConfig {
  public config: any = {};

  constructor() {
    this.config = {
      '/': {
        page: {
          title: 'Dashboard',
          desc: 'Latest updates and statistic charts'
        }
      },
      'my-page': { // <= add page URL
        page: { title: 'My page', desc: 'My page desc' } // <= Page name and description
      },
      ngbootstrap: {
        accordion: {
           page: { title: 'Accordion', desc: '' }
        },
        alert: {
          page: { title: 'Alert', desc: '' }
        },

// Other code

The result of the 4 steps is: