So what exactly is analytics and why should you want it? Analytics is a very broad term, but basically it refers to a system or dashboard for measuring and tracking what is happening on your website. Knowing what is happening on your website is the only way to be able to improve your website. When using analytics the depth you can analyse data to is unbelievable, however you would not need to do this from the beginning. Initially, just start with the basics. That is, how many people visited your website, how did they find you, what did they look at while they were on your website, and how long were they on your site for before they left. These metrics are next to useless in isolation, however over time you can see how they change and grow (or remain stagnant) and this is where you can see where work is required.
Is the number of visitors growing or not? You need to find a way to increase this
How did they find you? Are they coming from the same place, from another website, what are they typing in to Google to find you? Overtime are they finding you by typing in more different words or less?
How long were they are your website? Is time on your site decreasing or increasing? Are they visiting more pages or less with each visit. Are most of your visitors returning to your site, or are they brand new?

There are quite a few different analytics options to choose from, however the best (in my opinion) one, also happens to be completely free, and is Google Analytics. All you need in order to use it is a free gmail account/address, and so create one to use for this. Something like mycompanyname@gmail.com.
Once you have logged into your analytics account, simply follow the instructions, and the system will create a piece of code for you. You can then take this code and place it on every page pf your website and you are good to go. Give it a few days to start tracking stats and then log in to see what you have.