I have a LANTRA basic certificate in Chainsaw maintenance and cross cutting. NPTC do the same certificate (now called QCF level 2, it was CF30). If you wield your chainsaw anywhere in public this is the minimum you should get but, to be honest, it's the best basic course for 'home' use as well. It will make sure you don't get into any bad habits. You can choose your instructor from a number in your area but find one by recommendation.
When I took over the wood two years ago it had (and still has) a lot of large wind-blown and hung-up trees - these are the most dangerous ones to deal with (apart from climbing) so I looked for a course that would give me the confidence to deal with them. Unfortunately the LANTRA/NPTC route requires you to go through the levels in turn at considerable cost:
- Felling & processing trees up to 380mm (was CS31)
- Felling & processing tress over 380mm (was CS32)
- Felling uprooted and windblown trees (was CS34 & CS35)
It would have cost me over £1,000 to get to CS34 & CS35 so I paid for a two day course of 1 to 1 instruction (with Phil Dunford in North Wales) - it still wasn't cheap and I don't get the certificate but at least I now know how to do the work safely (and, more importantly, what not to tackle).
Chainsaws are killing machines; I recommend getting professional training.
As a bare minimum there are plenty of decent guides on YouTube. Husqvarna did a good series. Learn to sharpen (really not difficult) and wear proper PPE. Aside from some very small trees, I don't use mine for felling but it's easy to get blasé with a potentially very dangerous bit of kit.
Planning on getting a battery chainsaw next as so fed up of the running problems with both my Stihls.
All banging points in this thread. I don’t really feel I can contribute much more other than get professional training, and/or someone to mentor you.
I take it you want it for private use? See if you can work on cross cut first getting confident and work towards felling.
One thing I would add is make sure you have the proper clothing and PPE. Don’t mess with these things, they are lethal.
Get some upto date first aid training too. I used to keep a waterproofed contact card with everything on, grid references etc and any other information that might come in useful for the Emergency Services. And a trauma bag with Military field dressings and TQs.
And make sure you have someone nearby that knows what you doing/can help/call in Emergency Services.