I wish to have a dishwasher, a washer/dryer and a cold water tap on one cold water feed.
Can I connect them in series and does it need something else?

Water is not like electricity as "series". Typically you would run a 3/4" cold water line and bring 1/2" risers to each appliance and water tap. However, a dishwasher requires a hot water line. Except for some manifold PEX systems, that is how houses are plumbed. Are you building a house?