A simple method is to use a sterile syringe. Drop the seeds into the syringe. Suck up the seeds. Suck up the sterilising solution. Shake for required time. Squirt out nearly all the solution, nozzle down as seeds will flow. Suck in sterile water and shake well. repeat as required. The last time squirt out onto the medium.
I use syringes with 3% H2O2. If enlightened it will degrade into water and oxygen so it can go inside the flask with the seeds because it does not harm them.
I want to add that you might want to add a tiny bit of dish soap to your bleach solution to act as a surfactant. When I say tiny, I mean a drop or two.
I use peroxide to sterilize my dry seed, but I get a little frustrated because it gets foamy sometimes. I really want to try bleach like Royal suggests, but since I've never done it, I'm a little nervous. Most everyone else uses bleach. I don't know why I'm being a wuss about it.