Place the black rubber seal on the tip of the screw/piston.
Put 100 to 500 mg of tissue into the barrel of the plastic disposable liner. It is usually not necessary to pre-chop soft tissue.
Partially insert the screw/piston into the barrel of the plastic liner and slide this assembly into the stainless steel press cylinder.
Screw down the press. Depending on the tissue, extract exits from the pointed end of the liner in the form like liver paste or juice. Continue screwing down the press until all of the sample has been extracted. More pressure beyond this point can shear the plastic tip and force it out of the press cylinder. With very small samples, some of the extract may remain in the liner tip but can be removed with a micropipette or small spatula.
Unscrew the press and dispose of the used liner and the piston seal. The provided white plastic poker is sometimes helpful.