Official website - https://www.alien-rpg.com/
Attribute + Skill + Gear = number of dice rolled. If you have Stress Levels you also roll that many Stress Dice. Special circumstances or difficulties may reduce or increase the number of dice used. You need one 6 as a success. Additional successes increase the usefulness of the skill in various ways (these are called stunts and vary from skill to skill).
If you fail to get any successes, you can Push your Skill. You get 1 Stress Die (for the increased in Stress Level) and reroll any non-success die with your Stress Dice.
Any 1 on a Stress Dice is a Panic Roll.
A Panic Roll is 1d6 + how much Stress you have. A 6 or less and nothing happens. Things get worse if you roll higher than 6.
It isn't just pushing a skill that increases stress - many other things do. Firing a gun on full auto, taking damage, going without food, sleep, water, a scientist failing to analyse something, being attacked by a crewmember, an unexpected android, encountering something weird.
However - there are things that reduce stress as well.