To install the needed packages, run "npmi" in your terminal. Open another terminal and run "npm run start" to start your localhost server. Open another terminal and run "npm run seed" to seed the database so you are then able to test the backend routes in insomnia. Below I will attatch a video of me testing the routes.
https://drive.google.com/file/d/1wuOBmw6gVZOS_abQytRMKIj88i2mXKvy/view