The usefulness of Friel's training bible to a beginner is highly questionable, to say the least. Friel himself says, at the outset, that his principal audience is racing cyclists who wish to progress to the next level. His advice to beginners is to just ride steadily for a year before returning to his book.

His "cycling past fifty" is going to be more helpful but is still aimed at those who wish to be, or remain, fairly competitive.

OP, if you want useful advice you are going to have to ask useful questions. FWIW, I got back into cycling aged 49, about 40lbs overweight. I started by commuting, a round trip of 32 miles per day. I was unable to manage that five days per week at first, so to start with I commuted every other day. That lasted maybe three months, by the end of which five days a week was fine. I rode at a pace that challenged me, but didn't exhaust me, going hard enough to feel I was working but not so hard as to get out of breath.

That went on for about a year. I then started getting more interested in what I could achieve on the bike and began to do things that could be described as "training" as opposed to just riding to work. But there really isn't much point in talking about them until you've been riding much longer than the month or so that you have currently been at it.

At this stage I have only three pieces of advice.

1. Try to be progressive, building distance (first) and speed (later) by increasing your time on the bike gradually week-by-week. Key to this will be recovery. Rest long enough to recover ccompletely from each effort before making the next one. Riding every other day is probably ideal but don't be afraid to take two days off if your muscles are sore.

2. Sleep longer than you do now. When one returns to higher levels of physical activity one's need for sleep increases.

3. Sort out your diet. Just riding to and from work won't make much impact on your weight, you'll just eat more because the riding makes you hungry. So you need to be aware of what you are eating and drinking, and make sure you get your calories from nutritionally-dense foods. No "empty calories" like sugary drinks, careful limits on very high-fat stuff like pizza. The cliche runs "you can't out-exercise a bad diet " and it's not far from the truth.