The Leukaemia & Lymphoma Research Blenheim sprint triathlon is just five weeks away and this is my third week of training. In my last blog post, I explained why I have taken on this challenge. Now I am going to explain how.

Week three: How to wear a wetsuit with style and why the police stopped me on my 11-year-old daughter’s bike.

#ELLEfit team guru Tim Weeks sends me a personalised triathlon training schedule. A full-time job, combined with the diary of four busy school-age kids, means time is of the essence and training has to be balanced across the lives of six people (if you include my husband, who views my new-found exercise addiction suspiciously).

If you’re thinking of doing something similar, this is a flexible plan that won’t send you mad with guilt over missed sessions or time spent away from the family.

Tim’s plan:

Monday: Up to 60-minute swim. Run, bike, run for 40 minutes, if time.

Tuesday: Pilates/yoga/strength session of some sort. Or rest.

Wednesday: 60-minute swim. 5km run. With some speedier kms to raise heart rate.

Thursday: yoga/equivalent or rest.

Friday: 60-minute swim. 60-minute bike. 5km run.

Saturday: Run, bike, run sessions (60 minutes).

Sunday: Outdoor swim, 60 minutes.

I know I may not be able to manage all this but the structure is there to inspire me. There is also a great training plan on Marsha El Hage’s website.

1. 60 metre pool at Parliment Hill Lido in Hampstead Heath 2. Wetsuit (check), pedi (check), I'm going in 3. My daughter’s bikes 

The swimming element of this plan makes me nervous. There are seven of the #ELLEfitteam doing this sprint triathlon and I am by far the weakest swimmer. Last week I managed two lengths front crawl before breathlessly gripping the side, while a lady in her 70s congratulated me on getting better. But after four pool sessions, I am gradually improving. Swimming is about time spent in the water and I have been using a pull buoy (the float between the legs) which has helped my breathing - but it’s time to turn to the experts.

Enter Dan Bullock, a Speedo Advisory Coach coach with a manner that is as tranquil and pleasant as I imagine the lake at Blenheim Castle to be on a summer’s day. Dan is the lead coach at Swim For Tri and we meet him at Market Sports Health & Fitness Club pool in East London for a two-hour open-water swimming lesson. He isn’t concerned when I explain he’ll need to start with the basics. My first question: ‘How the hell do you put on a swimming hat?’ ‘Thumbs to forehead and stretch over the back,’ he replies, before showing us exactly how tight you need your open-water wetsuit to be. You need baby oil for arms and legs and anti-chafe cream for around the neck – there are so many clever tricks to getting this suit on. I will direct you to the Swim For Tri website because it’s an art and when you get it right, the thing feels like a second skin. He recommends a spare pair of goggles for race day and wearing two hats. Two hats? It breaks all the rules of fashion but they will keep your head warm and your goggles on.

Once in the pool our strokes are analysed and the sheer floatiness of those Blueseventy wetsuits makes life a million times easier. I don’t think I will ever swim without one again. Our swimming is filmed and helpfully sent over afterwards. We ‘drill’ swim to get used to bumping each other and learn about ‘drafting’ (which is like tailgating a car but you do it with the swimmer in front!). Then he drops the bombshell which makes us all feel better. After confirming he’s sure we’ll all make the 750m lake swim required after what he’s seen, softly spoken Dan tells us it won’t take longer than 30 minutes. In my head, this swim was an hour of battling the lake and swallowing weeds. Thirty minutes? What a relief.

Dan talks through what will happen so expertly and patiently, I feel we have been hypnotised into a newfound confidence. At this point I am tempted to enter an Ironman triathalon. That’s how happy we felt when we left.

4. Our Blueseventy Wetsuits 5. The lake at Blenheim Palace 6. Team #ELLEFit run with the GB Womens' Hockey team this week 7. Swim training with Dan Bullock at Swim For Tri

All we need to do now is master the bike. Four times around Regent’s Park near my home is 20km – the distance we ride after our swim and before our 5km run. This week I manage a 5km run followed by twice around the park and a 2km run immediately after. It’s like running with legs of lead and only Britney Spears on play and the thought of a huge slice of Bakewell tart at home got me through it.

I don’t have my own bike yet (as I said this is a beginner’s blog) so I’ve been borrowing my 11-year-old daughter’s bike. On the way to the park (in the rain), I accidentally drive down a one-way street the wrong way. I nearly leap off my bike in shock when a police car coming towards me ‘sirens’ me to the pavement.

When I explain this is my first time on a bike in 10 years, they take pity and I am tempted to cry. ‘Well done on coming out in the rain and giving it a go,’ the officer tells me. I am beginning to think this triathlon might actually happen.

THIS WEEK I HAVE BEEN

- Accidentally carb-loading. I don’t even know what that means, but fitness people say it all the time so I am too.

- Checking out Barrecore as a possible strength training exercise and trying to find a green juice I can make it all the way through the bottle with.

Week 3: Planning it all - how to fit training into your packed schedule, and stick to it. Plus, how to structure your training.