remove all tools and tool holders from the spindle

you will need to fold down the tab on the tab washer that's stopping the tab nut from turning. undo the tab nut and remove, remove tab washer. remove belt, undo pulley, probably two grub screws locking it to pin. remove pulley and pin.

id have to see a photo of how the bearings are sat around the spindle.

but there is probably a guard on the underside/spindle on the head to prevent crap from getting into the bearing, you will need to remove this. normally 4 allen key bolts.

once all the above is done and subject to how the bearings sits you may be able to tap the spindle down/out with a hammer. but use some wood so you don't damage the spindle. also put a car jack or something on the table to support the head whilst tapping with a hammer. you don't want to snap the z belt and have the whole head crash into the table.