Read the Master License Agreement. Select and click Next . Select the installation type:
msiexec /i "<Path to ArcGIS Desktop 10.8 installer>.msi" /qb ACCEPTEULA=yes ESRI_LICENSE_HOST=<License Manager Name> SOFTWARE_CLASS=<Viewer|Editor|Professional> SEAT_PREFERENCE=<Fixed|Float> INSTALLDIR="<Installation Path>" DESKTOP_CONFIG=TRUE install arcgis 10.8