As long as you use a proper pipe cutter rather than a hacksaw a pipe cutter will chamfer the edge inwards so no burr. I don't see why you would worry about an internal burr but a small half round file will get rid of that. Then to clean use wire wool. I don't know whether you are going to solder or use compression joints, I would solder but I would use pre-soldered fittings but that is only because I'm not very good with solder on a roll and tend to make a mess. Use plenty of flux inside the fitting and and on the cleaned joint. Get yourself a solder blanket to protect the surrounding stuff.
https://www.ebay.co.uk/itm/Flexible...hash=item568825bca1:m:m72EPwPfeuSYkyyK_sMIx2g
I have seen them a bit bigger than this and a little bit cheaper.
Someone no doubt will come along and say what a load of rubbish. That is the nature of this forum. But it is the way I have done it for years and it works for me. I am not a plumber but I was an electronics engineer and I do understand soldering techniques