Headlice??

The 1st time ever my kids have picked up head lice from school. I’m so annoyed.. They been going for 10yrs and never had them before so im a newbie how to deal with them. I’m off to buy some head lice treatments and stripped bedding to wash & tumble dry, teddies to, hoovered mattress, sofa and carseats. what other natural things can I use to help prevent or kill them if the treatment doesn’t work 1st time?