Getting Started. To get started go to the Steam home website. You will need a Steam log in to play. Once registered, go to the store and search Warframe. Once it is done downloading you will need to use your register info to get started.
In the Game. Once you start Warframe you will automatically be on a mission first thing to learn the basics of the game. Once you finish the mission you will be allowed to choose your mission that you will go on. You will be able to buy weapons and abilities.
Abilities. You can earn abilities on the battle field. You will pick them up from enemies once you kill them. You can use them to help you progress farther in the game.
Level Up. To level up you must first earn enough exp points. Then you will fight to prove that you are ready to level up. You will only be able to use on weapon in those fights.