First, read the spellbook carefully. Especially the small print and legal disclaimers. If it all checks out, go Hellblazer on this shit and get embroiled into a decades-long battle of withs with the lords of hell while watching all my friends die and losing everyone I ever loved.
Actually, that sounds like a terrible idea. Maybe just try to spread peace, love, joy and understanding. While tripping through time, space and meta-space ofcourse. Whoo, druggy adventures! I've read too many comic books. Invisibles was awesome, though.