You will need to talk to the Daycare Lady inside the Daycare building in order to be able to put 2 Pokémon into the Daycare at the same time however with the Daycare in Pokémon FireRed and Pokémon LeafGreen, the Daycare that is south of Cerulean City cannot accept 2 Pokémon. The Daycare in Route 3 in Pokémon Black and Pokémon White can accept 2 Pokémon but it will not be able to accept the second Pokémon until after you've reached Nimbasa City so that the Daycare Man will return to the Daycare.
Zoroark and Ditto.
OK this is how you put two of your Pokemon in the daycare then when you go out of the house go back in there then the guy will sit there.
put two Pokemon in the daycare 1 female and 1 male
put them in the daycare centre in solaceon town for a while
the daycare is in solaceon town.
put two ralts or the evolved forms of ralts in the Pokemon daycare and if they get along just run around for awhile until your poketech daycare app says you have an egg then go get it from the daycare and it will have a ralts in it
put any pokemon in the daycare with a ditto, then wait a day or two. it doesnt work with legendarys though.
After you beat the Pokemon league you should be able to catch ditto in the grass next to Canalave city once you do take it to the daycare and put them in there and wait a while ....... hope this works for you
you go to the daycare and put in two Pokemon if they like each other they will mate and have an egg you then go to the daycare man and he will give you the egg (you could also ask they daycare man if they like each other and it takes awhile for the Pokemon to make an egg)
take two Pokemon of the same kind and put them in the daycare center
Go to cerulean city.Go south of it using the move cut and go down the fenced area there will be the daycare. Put two compatible pokemon in the daycare, and wait. The man there will tell you if the pokemon made an egg.
you either need to put a ditto in with a poke (non ledgendary) or put in two Pokemon of the same type..sometimes its possible to breed with two different Pokemon you need to look that up on Google tho..=/~