What Is A Trial Of Ascendancy?
A Trial of Ascendancy is a mini-dungeon filled with puzzles and traps that you must navigate to reach the end. These trials do not require you to defeat a boss, but they often feature challenging enemies and environmental hazards that can pose a threat if not managed properly. Completing a trial involves overcoming these obstacles and reaching the final area.

Once you complete all trials in a given difficulty tier, you must visit the Sarn Encampment to interact with the Trial Plaque. The plaque will display circles filled in for each completed trial, providing a visual representation of your progress.

Normal Trials Of Ascendancy Locations
The first set of trials can be completed by Act Three of the game. Here are the locations for each trial in the Normal difficulty:

Act One:
The Prison (Lower Level): Found in the Prison area of Act One. Navigate the lower levels to locate the trial.
Act Two:
The Crypt (Level One): Located in the Crypt area. Enter the first level to find the trial.
The Chamber of Sins (Level Two): Head to the Chamber of Sins and explore the second level for the trial.
Act Three:
The Crematorium: Situated within the Crematorium area. Look for the trial in this fiery zone.
The Catacombs: Located in the Catacombs area. Complete the trial amidst the ancient tombs.
The Imperial Gardens: Explore the gardens in Act Three to find the final trial of this tier.

The link (https://www.mmoexp.com/Path-of-exile/Currency.html) leads to additional details about the game.