Is there anybody here, who has previous experience in making a product open source?

Publishing software + its code under a libre-free license is primarily an act to establish digital user rights and freedom. Practically, this requires the selection of a license, add license notifications, and then publish it somewhere (source code repository hosters like GitLab come to mind, but theoretically, with worse discoverability, you could publish it on your own website or even distribute the software via post mail order or e-mail or whatever). Ideally, instructions are provided about how to compile/install your software. If other developers want to contribute changes back to you (which they don't need, they could publish them themselves in an independent copy/fork of their own), it would be good to handle them by reviewing + incorporating/merging these in order to publish + package a new, updated version, if you're planning to stay the maintainer of the project. Also, users might submit bug reports, potentially publicly. Usually, almost all developers are totally busy with their own projects and there are just myriads of projects around and things to do, so it's not very likely that you get overwhelmed with contributions, to the contrary. That's where the part about investing heavily in building a community around the project comes in, which doesn't necessarily work out in the ways you hope or anticipate. The whole question is: with such a decision, what are your goals? If you want join the community of developers who respect each others digital freedom and the rights of the users, most steps should be fairly simple and straight forward. If the hope is that loads of developers will join the project and do all the work, be prepared for some disappointment. And even if it happens, then direction/coordination might develop towards something you might not necessarily want or appreciate. Full disclosure: Don't have experience with releasing a personal project of mine under a libre-free license, as for a long time I start them out under a libre-free license to begin with.