I'm guessing given her figure she does proper heavy weightlifting however that doesn't make a YouTube video that can be followed easily, same as jo wicks.
Heavy weightlifting can't really be taught through a video.
I agree about Caroline Girvan @Daisy03 - her body is obviously about diet (you can only stay that lean via diet) and some much heavier training than accessory workouts with hand weights. The main Pump instructor at my gym always starts the class by saying that pump will tone muscles, but won't develop them. It's different from weight lifting, and that's fine if that's what you want.
But there are various programmes where you could start - slowly - to move towards proper weight lifting. I like Jason & Lauren Pak and the physiotherapist who lifts really heavy, Adam Meakins (both on Instagram), and MegSquats & Eugene Teo (on YouTube). But you probably need to film yourself and be really analytical about your form.
I've recently been watching a young Instagrammer, under the name SydGrows. She does an interesting YouTube vlog about how she got started - just at her localPureGym, and I don't think she worked with a PT - just hung out enough with other gym rats and picked it all up. She's very young but down to earth about the gym.
A couple of sessions with a gym trainer might help.
The main thing is to be on a progressive programme. There are several around and several specifically for women.