Your primary goal should be to hunt down the actual on DVD.
The "Click to Download" dream goes like this: Find a single Google Drive link, a mega folder, or a torrent index that contains all 12 volumes, neatly organized. The reality, however, is far more complex.
When fans talk about the "Classic Collection," specifically volumes 1 through 12, they are usually referring to a series of DVD releases that curated the vast majority of the original theatrical shorts created by William Hanna and Joseph Barbera.