The plywood that I'm using is 33mm baltic birch.
The plies (layers) in plywood are run in alternating directions, so approximately half of the layers visible on any edge will be end grain and half will be the long grain. End grain usually absorbs more finish which makes it look darker. If you want to minimize the difference between the plies you could seal the edges of the plywood with shellac before you apply a top finish coat over the whole piece. Alternately, you could let the difference in the darkness of the plies be a 'design feature'.
Other than the alternating plies / darkness issue, the rest of the finishing depends more on how you want the table to look and how it is intended to be used.
The oil based polyurethanes do a good job (at a good price), but are not friendly to any mistakes, if you want a deep finish. If you sand through one coat, you get witness lines.
More forgiving (because they are faster drying) are the water bourne polyurethanes. They are clearer (than the oil) and harder (especially the crossed linked polymers)
Foam brushes or pad applicators are recommended.
I would recommend several 'edge only' coats to start, since end grain absorbs much more than face grain.