Here is a link to find ideas for celebrating the fall moedim (appointed times) of Yom Teruah, Yom Kippur, and Sukkot on the Homeschooling Torah website:
https://homeschoolingtorah.com..../category/blog/bibli
We want to be very careful to use the Scriptures as our primary textbook. There are many websites and books you can turn to for ideas on how Jews and Christians alike seek meaning in the traditions of the moedim. However, Scripture doesn't say as much.
We can turn to Leviticus 23 or to a few other passages, but outside of the Mishnah, Talmud, and rabbinic writings, I'm not exactly sure what celebrating these holidays -- in the dispersion and without a temple -- should really look like.
We do know this. Our family left the traditional Christian observances of Christmas and Easter because they were filled with pagan traditions, even though those traditions had been "Christianized" and were truly being used to memorialize the first coming of Yeshua our Messiah.
Now we're learning about new customs for the fall feasts, man of which aren't mentioned in Scripture and have questionable beginnings in Babylon -- even though they are truly being used to memorialize the second coming of our Messiah.
We're not sure where the line is for your family. I just hope you'll study, think, and pray about why you do what you do. Don't be too quick to set up new traditions, only to take them away from your children in another year or two. You can never go wrong by keeping things simple and by turning to Scripture until you're sure of what the Father wants you to do. Be sure to always know why you're celebrating. Be intentional, and base all of it in His unchanging Word.