From disk in loft you will need the offline patcher. Then you need to look at the various patch options and select the patches that match your setup. Thing is if I recall correctly you will need to download a series of patches and apply them in the correct order because Obsidian, unlike Bioware with NwN, didn’t release an overall patch. So you have been warned. (If I am wrong about this I’ll be very happy)
If this is too much bother you can always buy the fully patched version that includes both expansions and the dlc module from gog for an extremely (so it seems to me) reasonable price. Plus you have the bonus of knowing that it should install and play on modern systems. Choice is yours. I’m just letting you know your options.