You should be able to get a metal bar down the centre of the hub where the old spindle goes and tap the complete bearing out.
When you refit the new bearings make sure you do not damage them by tapping them in the wrong place for what you are trying to do.
Step one fit one bearing to spindle ( axle ) by using something like a socket that fits just over the spindle and contacts the inside bearing track. Do not hit the outer bearing track for this part of the job it will ruin the bearing.
Tap this into hub but this time you must use a much larger socket so you hit the outer bearing track.
Do the other side by driving the bearing onto the spindle as for the first side this will also push the bearing into the hub at the same time. warm the hub up as well to make it a bit bigger to help the bearing to slide in.
You can get bearing with no seals on them or single or double seals.