Do not worry. Both a personal folder and someone shared with you folder are easy to download from the web interface. First, either allow first party cookies or add exclusion to third party cookies blocked list.

Now, press application on folder. Press down the arrow until you find the download. Press enter. Wait for a while to allow google drive to compress your file and download it. Once it finishes compressing the folder, you will get the download option as usual like downloading a regular file. Hope it helps.