Prep + Weekend

Non-native speaker always mix the following combinations:

At the weekend
On the weekend
For the weekend
Over the weekend

What would be a simple explanation of the right context for each of them?

You may find the examples below useful.

During my apprenticeship, money was very tight, so I had to work at the weekend. []

It was a time when your team’s effort on the weekend set your mood for the week. []

To win 4-0 in the manner that we did was nice and it sets us up for the weekend. []

There is at least a foot of snow around the lake and more fell over the weekend. []