Add "un"steamed games to steam

[Sora ☆♛]

Ive downloaded Warframe and played it before i got steam.
Now that i downloaded Steam, i got the question : can i add it to my steam somehow?
btw. you can download warframe on steam too

[Metalcheff91]

You can add it to your library but as a non-steam game,so any achievements wont reflect on your steam account. Basicaly you just add the launch shortcut to your steam library