If you have just started cycling, the best advice for the first year or so is - ride lots. Dont get into structured training yet.
Generally speaking, in the early part, it is good to spend most of your time riding at a relatively easy pace - this is an effort which is faster than just riding idly and where you have to pay attention to the effort, but not high enough that you get winded or get lactic burn in your legs. The benefit of this is that it will build a good cardio base, and also it is easy to recover from this. If you want to throw in some harder efforts, feel free to do so, but dont kill yourself - in the long run, a hard effort today is going to reduce your ability to ride more tomorrow, and in the early stage, a heavy emphasis on volume is your friend.
It is possible to replace volume with intensity (eg, the Time Crunched Cyclist referred to above) but given that you have time, you will get the best results from putting in the volume. It also has the additional benefit of making it easier for you to lose the pounds as well.