This is the number of galaxies that they found and the instrument they used to locate them:

Some 883 galaxies – a third of which had never been seen before – were observed by scientists using the CSIRO Parkes radio telescope in Australia. While the former ‘hidden galaxies’ are located about 250 million light-years away from Earth, their comparative closeness in astronomical terms effectively means our own local neighbourhood of space just got a whole lot more crowded.

Here is a bit about the group of galaxies the Milky Way is in from wikipedia:

The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.

These galaxies however are likely out side of our group.

thanks to sciencealert.com for the great info