Using angular Text Editor with visual studio

Note that the error i get is in the app.module.ts file because every time i comment out this two imports [FroalaEditorModule.forRoot(), FroalaViewModule.forRoot()] in the imports array the error is gone.

this is the error:

I tried to install and use the Text editor using Angular CLI and every thing went smoothly and the editor worked.

I read that i should import (or include) the package reference to the system.config.js file but really i don't know how to do that because it's the first time i use angular with vs.