Ramp has two common meanings:

1. A sloped surface that connects two different levels, making it easier to move between them. You've probably used a ramp to roll a suitcase into a building, or seen a skateboarder ride down one. Ramps help people in wheelchairs get into buildings, and they make it easier to push heavy carts or move furniture. Before ramps, people had to lift things up stairs, which was exhausting and sometimes impossible.
2. To increase something gradually. When a factory ramps up production, it doesn't suddenly make ten times more products overnight. Instead, it slowly increases output week by week. A teacher might ramp up the difficulty of homework as students learn more. Athletes ramp up their training before a big competition, working harder each week so their bodies can adjust.

Both meanings share the idea of a gradual slope rather than a sudden jump. Just as a physical ramp makes climbing easier by spreading the height over a longer distance, to ramp up means increasing something steadily instead of all at once.