Hello Steven,
I have just cottoned to the fact that this is your first towing experience, and that has just set an alarm bell ringing. If you passed your driving test after the 1st Jan 1997, you are not licensed to drive the outfit you have, unless you have taken the +E extension to your standard Cat B licence. The standard Cat B only allows you drive an outfit of Maximum Authorised Mass (MAM) of 3500Kg. I do not know the MTPLM of the Sorento but its MIRO is at least 2 Tonnes and the MTPLM of the Lunar is 1800Kg so that is already 3800kg = already over the limit and that is without the actual maximum mass of the Sorrie. Please check you licence.
Assuming that you are ok with the licence - Quite a momentous decision, and as new tower please take it easy. I have suggested to a number of friends who took up caravanning and who had never towed before, to think of the outfit rather like a bus, slow to pull away, and needs to take a wide route round bends and islands. Just remember all the things you hate about buses when you are following one in traffic, and do the same. Don't forget your mirrors and use then, especially the near side, they are about the only things that keep you informed of what going on behind and at the sides. Where all the people who hate busses and caravans tend to find themselves and do silly things.
Best of Luck and enjoy the slower pace of life.