gulpがインストールできません

node.jsもgulpも初めての初心者です。
sassのビルド環境を入れたく以下のようにしました。

npm install gulp gulp-sass @frctl/fractal --save-dev

そうすると以下のように出力されました。

npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated coffee-script@1.12.7: CoffeeScript on NPM has moved to "coffeescript" (no hyphen)
npm WARN deprecated core-js@2.6.11: core-js@<3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
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 fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated har-validator@5.1.5: this library is no longer supported

> fsevents@1.2.13 install /Users/tanaka/style_guide/node_modules/glob-watcher/node_modules/fsevents
> node install.js

  SOLINK_MODULE(target) Release/.node
  CXX(target) Release/obj.target/fse/fsevents.o
  SOLINK_MODULE(target) Release/fse.node

> node-sass@4.14.1 install /Users/tanaka/style_guide/node_modules/node-sass
> node scripts/install.js

Downloading binary from https://github.com/sass/node-sass/releases/download/v4.14.1/darwin-x64-83_binding.node
Download complete  ⸩ ⠋ :
Binary saved to /Users/tanaka/style_guide/node_modules/node-sass/vendor/darwin-x64-83/binding.node
Caching binary to /Users/tanaka/.npm/node-sass/4.14.1/darwin-x64-83_binding.node

> node-sass@4.14.1 postinstall /Users/tanaka/style_guide/node_modules/node-sass
> node scripts/build.js

Binary found at /Users/tanaka/style_guide/node_modules/node-sass/vendor/darwin-x64-83/binding.node
Testing binary
Binary is fine
npm notice save @frctl/fractal is being moved from dependencies to devDependencies
npm WARN style_guide@1.0.0 No description
npm WARN style_guide@1.0.0 No repository field.

+ gulp-sass@4.1.0
+ gulp@4.0.2
+ @frctl/fractal@1.4.1
added 262 packages from 221 contributors, updated 1 package and audited 873 packages in 81.924s

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

found 4 vulnerabilities (2 low, 2 high)
  1 'use strict';
  run `npm audit fix` to fix them, or `npm audit` for details

コンパイルしようと、
gulp sass
すると、
-bash: gulp: command not found
となったためインストール出来ていないと気付きました。

ログを見ても何をどうして良いのか分かりません。
先輩方教えていただけないでしょうか？
宜しくお願いします。