Hi,
You are in good company regarding the Inon manual!
For TTL:
Advanced Cancel Circuit button in its "Off" position (i.e. Up).
Main switch set to STTL or STTL low
Ev Control switch in position "B". If this is not exposing correctly, you can use position "A" or "C" to lighten or darken the image respectively.
For Manual:
Advanced Cancel Circuit button in its "On" position (i.e. In).
Main switch set to "M" or Full.
Exposure control from -0.5 to 16 via EV Control Switch. If in Full mode, the EV control switch does not affect the output.
This should get you going. Cameras can be a little quirky too
Adam