you certainly don't need to predrill and countersink for the screws. just use 40mm x 4mm chipboad screws. get a magnetic bit holder and so long as you use good quality screws (spax or reisser) and a good quality screwdriver bit (and the correct type) then the screw will stick to the screwdriver bit and you will be able to screw it straight in.
if you use cheap screws, or a rubbish or worn out bit then the screw wobbles as you try to screw it in and it all becomes a bit of a chore.
if you use a good driver then you can sometimes screw them in on the fast speed, but that's a bit of an advanced trick for a beginner so best to steer clear of that.
a decent screwdriver is more than worth the extra money. they are lighter, more compact, more powerful and have longer lasting batteries, plus other useful stuff like electronic brake and one handed chuck, fast charger etc. 12v is more than enough for screws.