sleep training advice please mums 🙏🏼

helena
My  baby girl who is 17 weeks old has just hit the sleep regression 
She sleeps a solid 5-6 hours from 7pm -1am then after that she's up every 1-2 hours 
At what point do you start to introduce sleep training 
During or after the sleep regression ? 
It's only been going on 5 nights now so if I wait how long should I wait for? 
Advice please ladies