"Rack" is referring to transferring your wash from the fermenter to another container. It is more of a beer brewing term that comes from the use of a racking cane. You can google that or look on any beer brewing website and find a racking cane for a few dollars. It will have a clamp on it to clamp the cane to the side of your fermenter thus allowing the bottom of your cane to hover above the sediment while sucking the wash out.

"Clear" is just referring to either letting the sediment drop from your initial ferment or adding a clarifying agent such as irish moss or super kleer to your wash that binds the protiens and makes them drop better.

Both processes just clean up the wash a little better before you distill it so you have less off flavors or smells from heating the proteins, yeast, etc. up in your still.

After fermentation and racking to another container do I have to worry about bacteria? Keep it airlocked?

I didn't use the normal method everyone seems to be using. I added hot water to my grains aerated by shaking quite a bit, letting sit 24hrs aerated again then added yeast.
Fermentation took about 4 days.

Haven't checked with the hydrometer yet but it smells like there is alcohol in it.

Now I want to rack out what I can from the mash let it settle then rack it again before running. I have time considering nothing is going to be run for a few days. I just don't want to ruin my batch.