It can seem pretty daunting buying a telescope for the first time, but don't be alarmed, there are a few pointers that narrow down the choice available.
Well, it basically comes down to mirrors or lenses inside the actual body of the telescope and as both work equally as well in modern telescopes, it doesn't tend to make too much of a difference which one you choose. The reflector has the two mirrors and the refractor the lenses, but invariably with optical equipment, how much light is allowed onto the eye is the most important bit. The basic rule of thumb is a larger barrel size captures more light and a tip-top eyepiece helps with the detail. Magnification is important as is zoom, but remember that both will reduce light input as a matter of science..... the more magnification the less light, so the bigger the barrel needs to be. The quality of the glass and mirrors used in the telescope is also important as this gives the edge to edge quality and reduced colour fringing, so if the telescope is expensive, then generally the quality of the components is higher.
A telescope either comes with one or more eyepieces which can be swapped over depending on what we are looking at. A 30x eyepiece gives 30 times the magnification and eyepieces go up to around 300x magnification, depending on the length of the telescope barrel. With a larger magnification comes a restriction of the amount of sky that can be viewed through the scope, so if you think you are going to need a large magnification, make sure you line up the telescope first before looking through the eyepiece.
This is easy. The telescopes tend to come with a tripod which holds them off the ground and they can be carried complete with tripod if necessary. Find a place that has low, or preferably no light pollution and attach the barrel of the telescope to the tripod. The eyepiece can be removed and replaced easily and if you want the image to be the correct way round when you are viewing the night sky, the use an erecting eyepiece which usually fits in-between the eyepiece and the telescope.
Many telescopes work with an equatorial mount, which is a great accessory as it fits to the tripod and shows the lay of the land as far as the stars and planets are concerned. If you can run to a motorised equatorial mount, then the mount follows the night sky, so that you are always looking in the same area. Moon filters are really useful when the moon is at its brightest and sun foils are available for using the telescope during an eclipse.