Can I keep adding eggs during incubation and put them on Hatcher.

You can have some hatching in the Hatcher and some setting at the same time.  Example using Chicken eggs can be found on pages 15-16 of the user manual (link on our website)

Eggs can be loaded every 5-7 days. 2-3 days before you are about to have a layer hatch, change temperature / humidity to the ‘hatching” parameter values, even if you have eggs in the setting period.