Hi op, I can empathise, the actual starting can be the hardest thing, and it's harder if you're not sure what's what and how when etc.
I've just discovered the NHS have exercise videos on their website and apparently a plan to follow a bit like couch to 5k.
Scroll down to the last two paragraphs here:
www.nhs.uk/conditions/nhs-health-check/tools-and-technology-that-can-help/
I bought the MUTU programme which is an online postnatal exercise programme by a physiotherapist; it's a mix of Pilates and aerobic work. She also says to walk every day, so definitely try to do that. I bought it to help with hypermobility and a c section as I was quite unwell after my first child but it's actually a really good work out. It's over a number of weeks and the early weeks are incredibly gentle. She talks you through all the stretches etc. A 10-15 min Pilates session daily and the 30min work out around 3 times a week. Down side it's that it costs (it's cheaper on her birthday but that's in the summer!) I'm terrible at doing though and should do more, however now my son is older I'm going for swims and a weekly jog.
Other suggestions are:
12 minute athlete app (I think some is free) - HITT training is really effective for weight loss.
Adrienne on YouTube
Yoga studio app (basic one might cost but it's great)
Walk/ run/ monkey run up and down the stairs perhaps in 10 laps.
Skipping in your back yard with a rope - this is unbelievably hard as an adult; I could only do 3 minutes at first. I would only do that a couple of times a week at first with good trainers on!
Walking with baby in a sling - the extra weight from baby gives you a little more of a work out; get a good supportive sling for you and baby though like a connector or a boba, unless you like wraps. In fact doing things in the house generally with baby in sling is very good exercise. I'm so much stronger after this second baby due slinging and him being top centile!
(You need to time first slings with some babies well, when happy and fed and pop them in and walk out of the door immediately to distract and settle them.)
Finally you could see your Gp or health visitor as I know they are prescribing exercise for depression in some places so they may be able to advise something or somewhere. Classes are always best imo esp of kids can go. Could you find something at a weekend so your husband can have the kids?
Hope you find a solution soon.