For wordbank exercises take a few minutes to look through the following links which will have various lists of words. Pick out a dozen or so words that you like, whether you are drawn to them for their uniqueness, their sound, their meaning, whatever the reason, pick a bunch of words, at least 12. If any of the words' meanings are not crystal clear spend a little time both checking it out in the dictionary but also check through wikipedia for history of the word and its usage, if it's the name of a place or has some significance in the world aside from just its meaning. In your notebook take note of anything interesting that you come across. Be sure to look through all the related words and antonyms. You won't need to use all the words now, just some of them and it's good to have a pool to choose from.
Once you have your list, have done some research and have at least a half dozen notes try to following exercises.
1) Use three of the words in the same sentence. Then take those same words and use them in a new sentence but in the reverse order.
2) Use two of the words in a sentence of dialogue.
3) Write two separate sentences that each use one word from the wordbank and the word "seaweed".
4) Use two of the words in a phrase or sentence fragment that is under six words.
5) Either use the phrase from #4 as a title and write either a poem or a piece of short prose to fit it,
6) Use the colloquial name of a type of seaweed (listed in parentheses) and one of your wordbank words as the title of a short piece.