The Rebbe writes that when moving into a new home, one should first bring in a siddur, Chumash, Tehillim, and Tanya. Mezuzot should be affixed immediately (without a blessing), checked after thirty days, and replaced with a more beautiful one if desired. A chassidic gathering is encouraged.
https://www.torahrecordings.com/rebbe/igroskodesh/012/003/3972