That's almost as bad as the Sencore TR 110 Transistor tester that's also available in this SK sale. No instructions included. Someone's selling them online, for $22 for the original, & "just" $16 for a 15 page photocopy.
The 2 C cell batteries in it were dead, so I replaced them, put in a good 2N2222A, and set the knobs per the very limited instructions by the knobs. The reading was low, and kept dropping.
So, is the setup wrong, or did the 2N2222A die, or is the tester dying?