Help! This is my first winter as a bee keepers and I want to make sure my bees survive the winter. Should I do anything (supply them with fondant for example or leave them alone?). Should I even open the hive whilst its -3 outside?
Firstly, welcome to the forum public side, I can see you've been a member for a few months and it's good that that you have recognised that winter is always a risk for our bee colonies. It's something that a beekeeper needs to be thinking about as soon as they have taken their honeycrop off in August or September.
But ... never too late to do what you can. As has been said, we need a bit more information to be specific but ... the critical questions you need to ask yourself:
1. Have they got enough stores to see them through the winter. (This will depend on what you left them with when you took your honey crop and whether you fed them to top the stores up if necessary). If they are light on stores then fondant is your friend.
2. Have you treated them for varroa, ideally you would have done something around September time. (If not the it's not too late but the treatments are rather limited at this stage to Oxalic acid by trickling or sublimation).
3. WIth any luck you will have some insulation on top of the crownboard and any holes in the crownboard covered over and no gaps anywhere. The hive entrance should be reduced down to the smallest size.
These are very general comments - they will vary depending on where your bees are located but - it's never a good idea to open up your bees in winter unless it's absolutely necessary to add fondant so no - you should not be inspecting them or opening them up unless it is critical.
Tell us a bit more about your set up, what you have done so far and where your bees are located and I'm sure we can offer more advice. Whatever you do, try and avoid panicking - and doing anything in haste. We've all been first year beekeepers at some point so we recognise the feelings of 'what do i do now' so you are in good company here.