Can i add multiple webparts in my SPFX project for sharepoint server 2016 - classic pages. All samples are for modern pages like [this][1].

**I have following error:**

[![enter image description here][2]][2]


 [1]: https://www.youtube.com/watch?v=Sm5UocF8mcQ
 [2]: https://i.sstatic.net/Rr5wC.png