As with all DIY, preparation is everything; an extra half hour spent on preparation will save hours of grief in times to come.
A good quality hammer drill with sharp masonry bits; a selection of wall plugs or other suitable fixings; a decent screwdriver (electric if preferred); and, of course a good quality spirit level:- none of these will be needed on a farm job. All you need are some 6″ nails (8″ will do at a pinch) and something to bash them in with – my wife prefers to use a clog. Nail the brackets to the wall somewhere in the vicinity of their intended location, a slight slope will add character so don’t worry. No need to check for water pipes or electric cables buried in the wall, nature has a way of letting you know if you hit one of these. You may find that the nails have gone clean through the wall and into the adjoining room, this is normal, why not hang a picture on the points or simply bend the tips of the nails over for an even more secure fix?