As someone above said, it can feel quite isolated as a manager - especially if you stepped up from the team you are on.
In general, modern management theory suggests you need to get at least one person on side to turn a team - so it's important to find that person.
Laziness is complex, obviously, but for me the three key things would be that people need to feel appreciated, be incentivised and, in very basic terms, get some enjoyment/fun from their day-to-day work - what you can do in each of those areas will depend on the type of management role you have. 'moany' is not a very useful description - presumably they all moan about different things - maybe those things are important to them?
As a manager, I would say that to win trust (which you need if you want to be effective) you have to be fair, transparent and authentic - but you also need to have some kind of vision/purpose that your staff can understand and 'see' in your actions - even if they don't necessarily agree with it.
Management is very tough at first for many people - but it's also learnable, and reading about the science is good. One thing that helped me a lot when I first started was a couple of different courses that helped me categorise people into different personality types. Nowadays, I think it doesn't matter so much which particular categorisation you use - they are all tools that help you focus on different individuals' drivers / triggers / behaviours and reflect about how you can work with each different person to get the best performance, because the answer won't be the same for everyone.
Don't feel too despondent - it usually gets much easier over time.