When to add nutrients?

I think it would depend on your soil. If it has it then you would wait. I use fox farm happy frog and I usually don't add any nutes until the end of veg if I veg 2+ months. And autos are usually sensitive to them so go light.

With Autoflowers that is about correct but it depends on what substrate you use to grow them. When growing in soil, you should be fine without nutrients until flower. That is unless the plant starts to tell you otherwise, eg. Lower leaves start to yellow, deficiencies appear, etc. When growing in soiless mediums like coco coir you will need to feed from the get go, lightly but much more frequently. Autoflowers in general don’t like nutrients as much compared to photo period strains. Of course that varies from genetic to genetic but is a common trend among autos.