Steemit Food !!! How to Make food videos ????

Anyone making food videos? I'm learning how and am using my 50mm prime b/c it's best with low light. Sometimes, however, I want to zoom in on the hero. So I tried switching to the zoom kit lenses, 18-55mm and 75-300mm. I'm not even sure if these are the right lens. Anyway, I had set the focus to manual, tried to zoom in and out by changing the mm. I just don't get it

In my lay person terms, I want to start with a 50mm focus and then do close ups with smooth transitions. I could make multiple shots, each closer to the hero using the 50mm and edit it in a video app.
But I still need to learn how to zoom in on a hero using a zoom lens. (Funny thing is I did better when I went outside and from the porch zoomed in on my license plate using the 75-300mm. Nice capture but I don't want to eat a license plate) .
I'm still searching for written instructions for a beginner but maybe you know of a good one.
Thankyou steemians food!