Right. My child was 13 months when Covid started. I can tell you now, you cannot work effectively and if you try to, you will send yourself mad. I was fortunate in a way that everyone was in the same boat so there was less expectation of normal work. Also my partner was also working at home, so we could share the parenting.
I did the vast majority of my work while he was asleep. That meant either getting up at 5/6am and working until he woke up (don't waste time on showering), or working after he's asleep until midnight. You can't do both. Hopefully he has good long naps in the afternoon? Maybe drop the morning nap now, if not.
Schedule your work so anything you need to think about gets done when he's asleep - preferably when you're most awake. Plan to do admin and anything you can easily drop and go back to while he's awake.
Hide some toys and bring them out after a few days, so he has something new to play with.
Get a playpen or use a travel cot, fill it with books and interesting toys and put him in there when you really need to keep him safe and in one place.
If he'll watch Cbeebies, brilliant. I honestly feel like the presenters are my mates, after four months of almost constant Cbeeies in lockdown.
Good luck. It's not fun, you really shouldn't do it because you won't be doing a good job of anything, but it is do-able.