Characters have six characteristics:
They are rolled with 2D (a 2d6 roll) but can change later on in character creation or as a result of the game.
Characteristics and many other values in Traveller are written in a semi-hexadecimal format:
The characteristics are combined into a compact Universal Personality Profile (UPP).
785B38
^^^^^^
||||||<<- 8 Social Standing
|||||<<-- 3 Education
||||<<--- B (11) Intelligence
|||<<---- 5 Endurance
||<<----- 8 Dexterity
|<<------ 7 Strength
Each character will start at age 18 and have a series of "terms" in their career.
Each term grants the opportunity to gain skills, characteristic boosts, and resources. But each comes with the risk of death and lowering of characteristics at later aging.
It is likely you will have a character die in character creation. They make shirts about it.
As this is the best way to get skills, character creation becomes a push-your-luck game while trying to make due with the randomness like throws at you.
A skill means you have training and experience so you can perform under pressure during in high-risk situations. Even a level 1 in a skill counts for a lot (consider each level to be equal to a 4-year degree/training).
Many skills you can perform with death is not on the line.
Traveller progression is diegetic, meaning any advancements are things that happen in-world. e.g. getting a starship, making Cr100,000, upgrading to a laser rifle.
Skills and Characteristics can be improved but by training them. e.g. a physical fitness program, a study-abroad course in Medical. They will take a lot of time but are optional.