144h free visa - URGENT

Good morning, i am an italian citizen and I would like to use the 144h pass for the following itinerary:
1) Entebbe (ug) - Guanzhou by plane
2) Huangzhou - Hongkong by train
3) Hongkong - shanghai by train or plane
4) Shanghai - entebbe (ug) by plane

Is that possible ?

Which document will i need to prepare before the arrival and which ones at the arrival?
When stopping in HK I will need another Covid test to re-enter china?

Thank you a lot!