First you need to work out what is a reasonable distance for you to cover in a week (on each outing try riding smallish loops until you're tired for a week). You'll want to do about 30% of those miles in one lower intensity chunk, you might want to make this a long recovery ride*, & the rest spread out across the week at higher intensities. Every week try to increase your distance by 10-15% on all rides. This will work for about 10 weeks before you'll need to think about changing your training strategy, by this time you'll also have a much clearer idea of your strengths & weaknesses.
* A general estimate is your ave speed should be at least 20% slower on a flat ride to 40% lower on a hilly ride compared to your high intensity rides.