Read the first few chapters of "The Adventurer’s Manual.pdf" in the Pillars of Garendall folder before you start. Everything you need to know in order to begin playing Pillars of Garendall can be found right there.
The basics: Use the arrow or keypad keys to move your character, move onto an NPC (non player character) to talk to or attack it, Pillars is sophisticated to know the difference. The x key is the action key. Press the x key to use any object, talk to any NPC or attack any enemy within range. The x key is the block key. Use it to block attacks from enemies. The p key pauses the game.
Controls are explained fully in the Adventurer’s Manual in the section called Controls.