As I recall, you're in the UK - the ground is not yet frozen, so get them in asap, having first dug the whole area over thoroughly, not just digging holes and inserting the trees, especially if you have clay soil. If they're going in separate areas, just ensure you dig over where you want to plant 3 times the width and length you need for actual planting. I rather hope you've done this preparation already, but if not, you need to do it quickly. If you haven't done the prep already, then tread down where you've dug over prior to digging a hole and planting, but not too heavily - there's not sufficient time to let it settle naturally over a week or two. Tread down fairly firmly round the trees once they're in position, and keep a check for wind rock - there's a storm coming in, and there'll likely be more where you are, and high winds might loosen the trees.
It doesn't sound like you can plant within the next day, so it would be better to dig a trench, lay the roots of the trees in the trench (preferably without allowing the trunks to lay on the ground, more upright or at an angle) then heel soil back into place around them. This must only be a temporary measure - but it will give you a few more days to get organised and plant them out. If you have pots large enough to accommodate the roots without cramping or bending them, and some decent potting soil, pot them up temporarily, but its not ideal - these will have been dug straight out of the ground, and the ground is where they need to be.