Sam Fisher is back?

Follow the in-game instructions.

Use the ARROW KEYS to move around.
The SPACEBAR will allow you to take actions. Use 'Z' to leave bombs and press 'X' to detonate, when you're ready. Move onto the elevated tile to move to the next level. You can press up against a wall and move sideways to move with more stealth. You can also push crates by just stepping into its spot.
Don't skip the tutorial and instructions. This step is very important if you want to get your uber-cool moves sharp and slick.