Go to Google Scholar and sign in with your Google account (same as your gmail account, if you have one). If you do not already have a Google account, you will want to create one if you have more than a few publications you intend to import.
Once you are signed in, go to the Advanced Search options by clicking on the hamburger menu (three horizontal lines) in the upper-left hand corner of the screen and then click on Advanced Search.
You can search for all of your publications by entering your name in the field marked "Return articles authored by." You will want to search for multiple variations on your name (or alternative publishing names).
Click on the star in the lower-left hand corner of all appropriate records to save it to your library.
To see a complete list of all records you have saved, click on "My Library" in the upper-right hand corner.
Click on the box next to each record you want to import into ORCID. Once you have selected all records you want to import, click on the Down Arrow below the search box, and select "BibTex."
You should see a screen that looks like the file below. Either right-click on the screen and "Save As" as text document, or copy and paste the contents into a NotePad file. If you are using Windows 10, the second option might be necessary.
Once you have that file saved, you can go back to your ORCID profile and select "Import BibTex" under "Add Works" and select the file you have just saved.
Once you have imported the records, you will want to check their accuracy and correct any mistakes.