To fabricate the electrode on glassy carbon, you have to make active material slurry by dispersing your material in a suitable solvent and preferably ethanol followed by addition of PTFE binder. You must use PTFE binder in soluble form. PTFE powder is soluble in NMP but it may take longer time but the use of sonication can reduce time significantly.
Do not use PTFE pellets because the dissolution of these pellets is a tedious task.