You don't need to follow all these steps every time you login, make sure to save the client id and client secret, for reuse.

Already have a client_id and client_secret? or
If you choose to use Rclone by "tick Use Rclone client", you don't need to do steps 1-4. Jump to last step

If you experience an error message (Limit exceeded/Quota exceeded/Queries limit) when choosing to use Rclone. In this case,
you need to create your own client_id and client_secret. Follow the steps below:

For video tutorial, you can watch here: https://youtu.be/G7u9SucTMv0

1. Create a Google Cloud project

Go to https://console.cloud.google.com/projectcreate
Click Create. The console navigates to the Dashboard page and your project is created within a few minutes.

2. Enabling Google Drive API

Go to https://console.cloud.google.com/apis
Click Library. in the search box type "google drive" and press enter, click "Google Drive API", and click Enable.

3. Configure the OAuth consent screen

In the Google Cloud console, go to Menu > APIs & Services > OAuth consent screen. or click https://console.cloud.google.com/apis/credentials/consent
Select External, then click Create.

On the next page, you just need to enter:
- App name
- User support email
- Email addresses
Then click Save and Continue.

Next, click "Add or Remove Scopes". Scroll down and find "Manually add scopes", copy the url below:

https://www.googleapis.com/auth/drive
https://www.googleapis.com/auth/userinfo.email
https://www.googleapis.com/auth/userinfo.profile

paste it on "Manually add scopes" and click Add to Table > Update
Then click Save and Continue.

Next Test users, click Add User, and enter the email address that you will use in sharer.pw. and click Add
Then click Save and Continue.

4. Create access credentials

In the Google Cloud console, go to Menu > APIs & Services > Credentials. or click https://console.cloud.google.com/apis/credentials
- Click Create Credentials > OAuth client ID.
- Click Application type > Web application.
- Under Authorized JavaScript origins, click Add URI. Then, enter http://127.0.0.1
- Under Authorized redirect URIs, click Add URI. Then, enter http://127.0.0.1

Click Create. The OAuth client created screen appears, showing your new Client ID and Client secret. copy and save!

Almost done! now you have your own OAuth client (Client ID & Client Secret), make sure you save your client id and client secret, for reuse, if your login session expires.

THE LAST STEP

Now we can login, Go back to https://sharer.pw/altlogin

- Paste your client id and client secret in the proper fields, then click Get code.
(for Rclone, leave the fields empty. just click Get code.)

- Allow app access to your account and make sure you "tick google drive access", if you see an unsafe alert, click Continue

- After the process is complete you will redirect to http://127.0.0.1/?code=xxx.... and browser showing site unreachable

- Just copy the full url(http://127.0.0.1/?code=xxx....) and paste it into the code field, Then click Login.

If you follow the steps correctly, you will be successfully login.