fitness plan help

Alright so my brother is a fitness freak and wouldn't shut up until I agreed to a fitness plan he's going to make for me, I really really don't want to do it i'm the complete opposite absolutely hate any form of exercise - haven't exercised in like 12+ years (assuming walking to the fridge from the couch and back doesn't count lol)

I'm 28 years old, healthy height/weight etc (no idea how with the amount of **** I eat and the fact I drink lots of beer but hey ho) i've always avoided any sort of exercise as I have absolutely no interest in it and I hate the feeling of being out of breath which happens a lot doing things like walking 5 minutes to my mums so being the lazy git I am I take the car anytime I can

In fact it doesn't 'happen a lot' because i've always avoided anything that I know would get me out of breath, always take elevators instead of stairs, car instead of walking and always avoid doing any sort of heavy lifting etc etc

I don't think my brother realises just how out of shape I am I keep telling him doing 1 set of press ups will get me out of breath he probably thinks i'm being dramatic but i'm not, I agreed to his fitness plan thing just to shut him up apparently it'll be small things to start 3 times a week just doing press ups stuff like that before moving onto other stuff (I wasn't really listening tbh)

I'm not the type of person that cares about how I look or what others think of me etc but I did say i'll give it a go for 1 month and i'm a man of my word (well not really but he IS my brother soooo) so does anyone have any tips? Cheers.

If you don't like workout and exercise, then it is better for you to make a routine of walking after having dinner at least 30min ...