So I am not naturally fit. BMI 33, size 16, 40 years old and a 10 a day smoker.
Before lockdown I did an active job, shifts from 6-12 hours per day, in a restaurant with the kitchen in a basement, so basically spent all my time going up and down the stairs and that was no issue.
During lockdown I’ve not done any exercise apart from walking to the shop. My last day at work I did 14750 steps, now some days I’m doing less than 200, and most of those are going to the fridge to get another snack! 
Every 2 weeks I have a fairly active day where I do the big shop, clean and batch cook. I’m really worried, as this day kills my back, I’m in a fair bit of pain and have to stop for breaks.
I’m really worried about going back to work. Not because of Covid-19, but because I don’t see how my body will cope.
On the other hand I’m really really looking forward to being back, I miss the guests and staff so much.
Can anyone recommend any exercises on youtube of similar to start getting me ready?
Those for elderly/children/very unfit people would be perfect, but I just don’t know where to start.
Please help me and my lardass!