I also started doing workouts regularly when the quarantine began. At first, it was hard, but later I got used to a new regime. First of all, I think, it is better to understand what exactly you want to change in your body and choose the proper exercises. You can easily find them on the Internet. I personally didn't like how my back looked, so I started by losing it doing exercises from this source https://betterme.world/articles/.... After that, I switched to exercises aimed to keep my whole body fit.