Can a great physique be attained through workout at home without the help of a trainer?
I don't know what is your ideal of a "great physique" so I am going to assume you're looking to get lean at around 10 percent body fat with decent muscle mass. If that's not your goal don't proceed reading further.
Now, getting lean and bulking requires you to have a balanced, macro nutrient rich diet high in protein intake (which is a completely different and very dispersed topic to cover here). And, coupled with that you need to put your muscles through tension. A lot of tension.
A gym helps with the latter. But, being honest here, it's very difficult to set up your own gym at home. Benches, bars, barbells, dumbells and free weights enough to keep you challenged and motivated. It's quite an investment. I'd suggest you to instead step outside the house a little bit and go for calisthenics.