Solar lights work because they contain rechargable batteries that are fed energy via the solar cell during daylight hours. This energy is stored in the batteries until it is needed after sunset when it is released to power the lights LED bulbs - there should be enough power to light up your yard for the entire night.
At the less expensive end of the market, most solar light units will have their own built-in solar panel to collect the Sun's rays. Once the solar panel has fully charged the battery, an automatic light sensor will control when the light is on or off depending on the amount of natural light there is - off during daylight and on at night. You can really just set and forget your solar lights, set the timer and leave the lamps to do the rest!
You can fix your solar lights pretty much anywhere you choose, although it's best if you choose a location that is not too shady - the latest solar fixings mean you can site your lights on your deck posts, in the ground, hanging from hooks, or you can even have them wall-mounted. The installation costs should be much lower than for standard lights, because there is no cabling to lay, no electricity points to fix up, and no trenches to dig for cables and the biggest saving you will make........no electrician to pay!
There are different types of light you can buy that powered by solar energy, for example the solar spot light. This is a great light if you are trying to pick out a particular feature in your garden such as a fountain, a statue, or just and area of your deck. If you need more light, solar powered flood lights are some of the brightest solar lights you can get your hands on and will litteraly flood an area with light if it is needed - this type of fitting is great to help with security.
Don't forget your deck when you are designing your lighting scheme, in my opinion, solar lighting works better with decking than any other material due to the many different types of lights you can buy. The easiest place to start is with some deck post lights, these can simple be fixed to the top of the posts and will add a lot of style to your deck on their own. If you want to make your deck really stylish, think about installing some small recessed lights around the edges of the deck and to light up any steps you might have.