As said above, you have to push the stapler really really hard onto wood (or whatever you are stapling) before the trigger will depress.
Sherry
February 2023
You have to push the front of the stapler down very hard against whatever you're stapling - concentrate force at the very front or it won't fire.
Frenella
April 2022
There are two black metal wings sticking out - 5cm from where staples are emitted
Hold the two black wings between finger and thumb and pull back and then out - this will release the staple cartridge arm - insert your staples from the front pushing the spring mechanism back.
Pull back two wings and re-insert.
Pressure needs to be applied to baseplate for machine to fire.
metcalfe_mike
August 2018
loaded the stapler and the yellow button will not depress to discharge the staple
madeline
December 2017
I have the same problem, did you ever get an answer .