in the Create event, set "bosshealth=60" or any variable name like "applehealth=60"
then set if collision with bullet, "bosshealth-=1"
for jumping around you can use codes or path, which one do you wanna use? codes are more precise but paths are easier
to shoot, I suggest using Alarms, in the create event, set like Alarm[0]=100
then add an Alarm 0 event, put in whatever attacks you want, then the boss will attack at the count of 100