CKEditor5-enterのインストール&使用方法を知りたい

前提・実現したいこと

前提としてckeditor5とnpmはインストールできている状態です。
実現したいこととしては、ckeditor5-enterをインストールし、Enterによる改行を<br>で行えるように
したいです。
プログラムの設定はこの参考サイトの「Enterで<br>を挿入する」をもとに作成しています。

発生している問題・エラーメッセージ

発生している問題としては、
コマンドで「npm install --save @ckeditor/ckeditor5-enter」を実行した際に

npm WARN old lockfile
npm WARN old lockfile The package-lock.json file was created with an old version of npm,
npm WARN old lockfile so supplemental metadata must be fetched from the registry.
npm WARN old lockfile
npm WARN old lockfile This is a one-time fix-up, please be patient...
npm WARN old lockfile
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated chokidar@2.1.8: Chokidar 2 will break on node v14+. Upgrade to chokidar 3 with 15x less dependencies.
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated querystring@0.2.0: The querystring API is considered Legacy. new code should use the URLSearchParams API instead.
added 1119 packages, and audited 1120 packages in 1m

69 packages are looking for funding
  run `npm fund` for details

9 vulnerabilities (8 moderate, 1 high)

To address issues that do not require attention, run:
  npm audit fix

To address all issues (including breaking changes), run:
  npm audit fix --force

Run `npm audit` for details.

といった内容が表示され、package-lock.jsonとpackage.jsonが作成されていました。
この２つが作成されているのとエラーではなく警告であるためインストール自体はできているとは思うのですが、
正しくできているのかわかっていない状態です...。
ckeditor5-enter自体は一応作成して変更も行ったのですが反映されていません。
間違っている部分や、足りていない部分などわかる方がいましたらご教授お願い致します。

該当のソースコード

作成されたJSONはこの２つです。
・package.json

json
1{
2  "name": "ckeditor5-custom-build",
3  "author": "CKSource",
4  "description": "A custom CKEditor 5 build made by the CKEditor 5 online builder.",
5  "version": "0.0.1",
6  "license": "SEE LICENSE IN LICENSE.md",
7  "private": true,
8  "main": "./build/ckeditor.js",
9  "devDependencies": {
10    "@ckeditor/ckeditor5-alignment": "^29.0.0",
11    "@ckeditor/ckeditor5-autoformat": "^29.0.0",
12    "@ckeditor/ckeditor5-basic-styles": "^29.0.0",
13    "@ckeditor/ckeditor5-block-quote": "^29.0.0",
14    "@ckeditor/ckeditor5-dev-utils": "^25.2.4",
15    "@ckeditor/ckeditor5-dev-webpack-plugin": "^25.2.4",
16    "@ckeditor/ckeditor5-editor-classic": "^29.0.0",
17    "@ckeditor/ckeditor5-enter": "^29.2.0",
18    "@ckeditor/ckeditor5-essentials": "^29.0.0",
19    "@ckeditor/ckeditor5-font": "^29.0.0",
20    "@ckeditor/ckeditor5-heading": "^29.0.0",
21    "@ckeditor/ckeditor5-highlight": "^29.0.0",
22    "@ckeditor/ckeditor5-image": "^29.0.0",
23    "@ckeditor/ckeditor5-indent": "^29.0.0",
24    "@ckeditor/ckeditor5-link": "^29.0.0",
25    "@ckeditor/ckeditor5-list": "^29.0.0",
26    "@ckeditor/ckeditor5-paragraph": "^29.0.0",
27    "@ckeditor/ckeditor5-source-editing": "^29.0.0",
28    "@ckeditor/ckeditor5-table": "^29.0.0",
29    "@ckeditor/ckeditor5-theme-lark": "^29.0.0",
30    "@ckeditor/ckeditor5-typing": "^29.0.0",
31    "@ckeditor/ckeditor5-upload": "^29.1.0",
32    "css-loader": "^5.2.6",
33    "postcss": "^8.3.5",
34    "postcss-loader": "^4.3.0",
35    "raw-loader": "^4.0.2",
36    "style-loader": "^2.0.0",
37    "terser-webpack-plugin": "^4.2.3",
38    "webpack": "^4.46.0",
39    "webpack-cli": "^4.7.2"
40  },
41  "scripts": {
42    "build": "webpack --mode production"
43  }
44}
45

・package-lock.json
一部のみ

json
1    "node_modules/@ckeditor/ckeditor5-enter": {
2      "version": "29.2.0",
3      "resolved": "https://registry.npmjs.org/@ckeditor/ckeditor5-enter/-/ckeditor5-enter-29.2.0.tgz",
4      "integrity": "sha512-SSzUZ6iTI1Tymgvol/3HEdsOoMnu6GRl0wdBUizMBqP6SkCLU6t+Zdayz/aRNnU9slLXl0pJyz/aD9jR0N6gKg==",
5      "dev": true,
6      "dependencies": {
7        "@ckeditor/ckeditor5-core": "^29.2.0",
8        "@ckeditor/ckeditor5-engine": "^29.2.0",
9        "@ckeditor/ckeditor5-utils": "^29.2.0"
10      },
11      "engines": {
12        "node": ">=12.0.0",
13        "npm": ">=5.7.1"
14      }
15    }
16