Usually you use VMware Update Manager to install VIB’s such as Dell’s Open Manage. You can also SSH into a host and use ESXCLI.
First upload the Offline .Zip file to your datastore. Then you will need to find the mount point.
esxcli storage filesysem list
Now that you install the VIB.
esxcli software vib install -d “/vmfs/volumes/Datastore/DirectoryName/“
esxcli software vib list