Try searching the web. If you aren't sure, you can ask the websites chat and Export Portal's Customer Support.
I have searched throughout the Internet, but could not find the specific HS code for the products I have, so I chose the most relevant ones to them.
I have asked the Customer Support team and they gave me the right HS Codes for the products I intended to sell.
You can search them on the internet, there are many websites that provide this kind of information.
5You can find the link https://hts.usitc.gov/ next to HS field adding an item.