How to host the app from Heroku?

[CatchMeIfYouCan4401]

I tried to edit and host the app from Heroku but I get this error. I have not much idea about how the app works, can somebody please help me? I have already edited the app, I just need to host it.
Please suggest me any free hosting service, where this app can be hosted. Here are the logs from heroku logs --tail

2020-08-08T07:21:40.808645+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-08T07:21:42.000000+00:00 app[api]: Build succeeded
2020-08-08T07:21:42.774735+00:00 app[web.1]: npm ERR! missing script: start
2020-08-08T07:21:42.781097+00:00 app[web.1]: 
2020-08-08T07:21:42.781390+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-08T07:21:42.781528+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-08T07_21_42_776Z-debug.log
2020-08-08T07:21:42.839619+00:00 heroku[web.1]: Process exited with status 1
2020-08-08T07:21:42.872202+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-08T07:21:42.877912+00:00 heroku[web.1]: State changed from crashed to starting
2020-08-08T07:21:47.935273+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-08T07:21:50.761153+00:00 app[web.1]: npm ERR! missing script: start
2020-08-08T07:21:50.766210+00:00 app[web.1]: 
2020-08-08T07:21:50.768292+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-08T07:21:50.768411+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-08T07_21_50_762Z-debug.log
2020-08-08T07:21:50.836997+00:00 heroku[web.1]: Process exited with status 1
2020-08-08T07:21:50.883340+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-08T07:22:56.601343+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=particle-portfolio.herokuapp.com request_id=8eb76f56-cae5-4693-9c8f-85dae30609ce fwd="157.47.135.93" dyno= connect= service= status=503 bytes= protocol=https
2020-08-08T07:22:58.984548+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=particle-portfolio.herokuapp.com request_id=e903bdcd-358e-4aee-8c0b-17625c4836d3 fwd="157.47.135.93" dyno= connect= service= status=503 bytes= protocol=https
2020-08-08T07:23:49.523899+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=particle-portfolio.herokuapp.com request_id=0657d084-1231-47d9-b830-5214ba43c6cf fwd="157.47.135.93" dyno= connect= service= status=503 bytes= protocol=https
2020-08-08T07:23:50.689551+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=particle-portfolio.herokuapp.com request_id=cb409d0d-caa1-467c-b2b1-329d286a2eaa fwd="157.47.135.93" dyno= connect= service= status=503 bytes= protocol=https
2020-08-08T07:43:53.989421+00:00 heroku[web.1]: State changed from crashed to starting
2020-08-08T07:44:08.192068+00:00 heroku[web.1]: Starting process with command `npm start`
2020-08-08T07:44:11.150054+00:00 heroku[web.1]: Process exited with status 1
2020-08-08T07:44:11.187605+00:00 heroku[web.1]: State changed from starting to crashed
2020-08-08T07:44:11.088405+00:00 app[web.1]: npm ERR! missing script: start
2020-08-08T07:44:11.097675+00:00 app[web.1]: 
2020-08-08T07:44:11.097984+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2020-08-08T07:44:11.097985+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2020-08-08T07_44_11_090Z-debug.log

[pranavnt]

In the package.json, there isn't a script for start, and only a dev script is included (Heroku requires a start script to my knowledge). You can fix this issue by adding a start script to your package.json.

[CatchMeIfYouCan4401]

@pranavnt I have tried that, but it did not work.
Please guide me what to write and where, because I have no experience with web development.
It would be nice if you could host this on heroku and put it on your GitHub account and I can see it from there, because I have been struggling with this for many days.

[pranavnt]

@CatchMeIfYouCan4401 Is the error still the same?

[CatchMeIfYouCan4401]

@pranavnt not the same error, a different error.
It would be very nice of you if you could host this on heroku and put it on your GitHub account :)