Let's say you are getting "It's taking a long time to install dependencies" during the yarn install step when attempting to create your backstage app.

I would probably do as the message suggests and press Ctrl C to exit. 

Installing dependencies:
  init          git repository ✔
  executing     yarn install ◜
⏱️  It's taking a long time to install dependencies, you may want to exit (Ctrl-C) and run 'yarn install' and 'yarn tsc' manually

Then move into the directory for your backstage app. For example, if you named your app "backstage" then there should be a directory named "backstage" in your present working directory.

cd backstage/

The directory should contain something like this.

~]$ ls --long
-rw-r--r--. 1 ec2-user ec2-user  150 Dec 30 07:09 README.md
-rw-r--r--. 1 ec2-user ec2-user   74 Dec 30 07:09 app-config.local.yaml
-rw-r--r--. 1 ec2-user ec2-user 2232 Dec 30 07:09 app-config.production.yaml
-rw-r--r--. 1 ec2-user ec2-user 4216 Dec 30 07:09 app-config.yaml
-rw-r--r--. 1 ec2-user ec2-user   26 Dec 30 07:09 backstage.json
-rw-r--r--. 1 ec2-user ec2-user  350 Dec 30 07:09 catalog-info.yaml
drwxr-xr-x. 3 ec2-user ec2-user   59 Dec 30 07:09 examples
-rw-r--r--. 1 ec2-user ec2-user 1596 Dec 30 07:09 package.json
drwxr-xr-x. 4 ec2-user ec2-user   49 Dec 30 07:09 packages
-rw-r--r--. 1 ec2-user ec2-user 1635 Dec 30 07:09 playwright.config.ts
drwxr-xr-x. 2 ec2-user ec2-user   23 Dec 30 07:09 plugins
-rw-r--r--. 1 ec2-user ec2-user  331 Dec 30 07:09 tsconfig.json
-rw-r--r--. 1 ec2-user ec2-user   85 Dec 30 07:09 yarn.lock

And let's see what yarn install returns.

yarn install

If yarn install hangs, you may want to try yarn install with certain flags. Also, check out my article yarn hangs at Resolution step.

yarn install --refresh-lockfile
yarn install --check-cache
yarn install --check-resolutions