The bleeder screw is supposed to be on the clutch slave cylinder, which is located at transmission at clutch release lever
Is the clutch slave and master cylinder new? If so, did they come pre-connected by the hose?
It is either original equipment or a very early replacement unit. Originally out of the factory, the unit was sealed(having been pre-bled before installed). The original replacement units were also the same. Eventually they did come out with separate replacement parts, including a slave cylinder with bleeder screw.
The only thing you can do is try to loosen the hose at the slave cylinder, but if there is air in the slave cylinder this of course wont help.
Most likely you are going to have to replace the slave cylinder with one with a bleeder screw.
But if you are having to try to bleed the system, then there is a problem with either the master or the slave cylinder anyway.