dot and dabbing is fairly easy and staright forward use 12mm moister resistant everywhere apart from the shower area use a cement board there some can be adhesive on some cant so you may have to batten out a little bit but from reading your posts you are studwalling so that's all ok if you dot and dab using 8x4s I allow 1 bag of drywall addy per 2/3 boards depending on how far out the walls are you will need a solid bead of addy at somepoint behind the board for fire regs I put mine at the top and if you get the nack and get all your dots and the solid bed something like the same depth place the board onto the addy lift up off the floor tight to the celling with a pry bar and wedge then tap into level and squaire I use a 1800 and a 1200 level for dot and dabbing and a framing square from screwfix to ensure my internal corners are true in all ways when dot and dabbing give the walls a quick coat of srb thinned with water about 1 parts srb to 2 parts water and remember if your tilling it the plasterboard can hold more weight in tiles and adhesive unskimmed than it can when fully skimmed so just tank where appropriate and tile the lot hope this helps