A tip I would suggest is to not recreate assignments and quizzes on formative. You can upload a current electronic document from Google docs, Word, PDF, etc. into a formative. All you would need to do is provide the questions on the already created document on formative. I have provided an example of what it will look like.
https://goformative.com/formatives/60ad2a9dbb927c0de77c20d5?preview=true