Starting Allium 'Purple Sensation' from seeds is very, simple. At least if you do it the way I do, as I just let nature handle it.
Just plant a few bulbs, and let them go to seed.
Normal gardening chores, such as weeding and so on will bring enough seeds to the correct depth for germination.
Very early next spring you will have masses of seedlings, probably more than you ever need.
So the only thing you will have to do is to let them be a bit undisturbed over winter and spring.
If there is plant debris and leaves in the garden, I will often see seedlings underneath these, when I clean up in spring.
Here in Sweden there is at least no need to do anything else. That said I do not know if more steps would be required in Texas for germination, as the climate is very different. The soil here is naturally moist during autumn, winter and into early spring, so that might promote germination.
