new references to VNF Onboarding Guidelines

For detailed instructions on how to add cloud-init or charms to your VNF, visit the following references:

- [VNF Onboarding Guidelines, Day-0](http://osm-download.etsi.org/ftp/Documentation/vnf-onboarding-guidelines/#!02-day0.md)

- [VNF Onboarding Guidelines, Day-1](http://osm-download.etsi.org/ftp/Documentation/vnf-onboarding-guidelines/#!03-day1.md)

- [VNF Onboarding Guidelines, Day-2](http://osm-download.etsi.org/ftp/Documentation/vnf-onboarding-guidelines/#!04-day2.md)

- [VNF Onboarding Guidelines, Day-0](https://osm.etsi.org/docs/vnf-onboarding-guide/02-day0.html)

- [VNF Onboarding Guidelines, Day-1](https://osm.etsi.org/docs/vnf-onboarding-guide/03-day1.html)

- [VNF Onboarding Guidelines, Day-2](https://osm.etsi.org/docs/vnf-onboarding-guide/04-day2.html)

Furthermore, you can find a good explanation and examples [in this presentation](http://osm-download.etsi.org/ftp/osm-6.0-six/8th-hackfest/presentations/8th%20OSM%20Hackfest%20-%20Session%207.1%20-%20Introduction%20to%20Proxy%20Charms.pdf)

If you want to learn more, these additional contents are highly recommended:

- **[VNF Onboarding Guide](http://osm-download.etsi.org/ftp/Documentation/vnf-onboarding-guidelines).** This guide includes all that you might need to onboard your VNF or applications in OSM.

- **[VNF Onboarding Guide](https://osm.etsi.org/docs/vnf-onboarding-guidelines).** This guide includes all that you might need to onboard your VNF or applications in OSM.

- **[OSM Developer Guide][developer-guide].** If you want to contribute to OSM development, it is highly recommended reading this guide first.

- **[Contents from latest edition of OSM Hackfest][latest-hackfest].**

- **Sample VNF Packages.** This page is under elaboration, but you can find relevant contents in these locations: