The chain like structure on the right is not like any of the plankter types suggested in step 2.
This is worrying 😦
Don't worry if you made some mistakes. Each image is classified by multiple users 😃 Here is a Field Guide with 4 image examples for each type of each category. You can have it opened in another browser tab/window during the classification and it will help you to recognize them more easily.
The best way to learn is to ask questions and read the comments to each image on the Talk. We are here to help you if you're having any troubles 😃 Don't give it up. It isn't as difficult as it seems to be for the first time. It just needs a bit of patience 😃
Good luck, feel free to ask!