Amateur,
There is no need what-so-ever to place a click-clack in a larger enclosure. Some people do because they have a large enclosure hanging around doing nothing. All it would do is to help stabilise ambient air temperatures in an environment that big range in temperature. You can achieve exactly the same effect by placing the click-clack in a wooden bookshelf or in a room inside a house (as against a shed).
Take the time to read the references posted. There is excellent information that will answer most of your questions. Have a pen and paper handy at the same time to jot down anything that needs explaining or other questions as they come to mind. Then ask them here.
One thing I strongly recommend is that you ensure you find a reliable supplier of quality frozen rodents that is easy for you to access. This will also allow you to determine what the on-going feeding costs will be so you are sure you can afford it. Like all pets, there is the possibility of a vet visit. Find a reptile vet in your area before you need one and make sure you can afford the bill, if and when it happens.
Oh yeah. Pine enclosures need to be waterproofed by painting with a waterproofing compound. 3 or 4 coats of polyurethane will do the trick and looks good. Many keepers prefer melamine for that reason, with the joins sealed with non-toxic silicon sealant, such as the acetic acid cured ones they use on aquarium construction. A waterproof cage allows for thorough cleaning and disinfecting, which will need to be done at times. URS produce moulded plastic cages partly for that reason.
Good luck,
Blue