The Moment You Touch Your Lulav, You've Entered Into Machloikes

Source SheetShould one get an Esrogs before or after yom kippur?Do some of the Minim need to be bound together? Do you need to hold all 4 at once to be Yotzei?If you don't have all 4, should you take what you have?Do you need to hold them in both hands? What if you held Lulav in the left hand and Esrog in the right?Which do you pick up first? Which do you put down first?