If you get "Rate Limit Exceeded" error wait a minute and try again.
1. Log in.
Click on the Select account button. If you logged in before you can select your account from the list. If you want to add a new account click on the Get auth button, follow the steps on screen, copy authorization code, paste it to the input field and press Continue.
After logging in you will see your name, email and free space on your drive listed in the first box. Click on the Switch button to switch to another account.
2. Select destination folder and manage your files.
The second box lets you manage files on your drive. Click on the Select button to choose the destination folder for copied files. Click on the Reload button to load list of your files in this folder again.
Only files copied using this tool are displayed there!
Select some files and press Share to copy their public links - this is useful if you're using JDownloader for downloading files. Click on the Delete or Trash buttons to remove files completely or move them to the trash.
3. Copy files
Paste encrypted folder ID or a normal folder link to the input field in the third box and press Load.
If you use encrypted folder ID then your access token is sent to the decryption server. Lifespan of that token is one hour. That means for one hour that server has access to your whole Google Drive! That's why you should always use a dummy account. The default decryption server code doesn't store anything but all it takes is one malicious person with a modified decryption server to wipe out your Google Drive or worse, steal your data. If you're using encrypted folder IDs with your main account - make sure you trust the person that shared it.
Click on the .MD5 button to download MD5 hashsums for all listed files. Select some files and press Copy to copy them to your drive.
Best practices
If you're just downloading files - use a dummy acc. Copy files to your drive, download them and then delete from your drive.
Tip: if your destination folder is already made public all files copied to it are public too, that saves you some time.
If you want to store files on your main account - open two tabs. In the first tab log into your dummy account and use encrypted folder ID to copy files to dummy account. In second tab log into your main account and use folder link from the dummy account to copy files from dummy account to your main one.