Find and purchase or download the Grimoire Encyclopedia, study up on every known medieval Grimoire and all of the spirit names and summoning techniques, and nowhere in any of that will you find reference to a character named Baphomet.
The closest I've seen is references to Mahomet, but they were referring to the prophet of Islam.
Baphomet is the synthesis of opposing forces, and the formula of the alchemical work, solve et coagula.
Eliphas Levi's rendering of the concept has been adopted as the team mascot of certain activist organizations.
To study Baphomet, read Levi, or Baphomet the Temple Mystery Unveiled by Twyman and Rivera, or The Mass of Baphomet by Nathan Harris, or any of the other readily available material out there.
To lear about commonly evoked spirits in the context of ceremonial or Solomonic magic, and how it all works, try Poke Runyon's The Book of Solomon's Magick for starters.
Happy trails.
