If you would prefer a visual helper of how to use the weapon in Relock then you can go:
Firstly you must understand how a weapon functions and cycles, this may seem complex but is rather straight forward I will separate this into seven stages.
Stage 1 - Insert magazine with ammunition.
Stage 2 - Prime weapon by pulling back the slide.
Stage 3 - Release safety catch (this can happen automatically on the C2 when priming)
Stage 4 - Squeeze trigger to engage firing pin which strikes cartridge primer and fires the round.
Stage 5 - Slide is forced back from blowback gases
Stage 5 - Empty cartridge is ejected via ejection port
Stage 6 - New cartridge is pushed from magazine into upper receiver via magazine spring.
Stage 7 - Slide forced forward by return spring
end of weapon cycle.
CitySec CSC-C2 Controls.
'R' & 'E' buttons simultaneously to eject the magazine.
'F' to insert a new magazine.
'Q' to release the slide forward if it is locked back.
'V' to release the safety mechanism of the firearm.
LMB (Left mouse button) is used to fire the weapon.
RMB (Right mouse button) is used to aim down weapon sights.
I hope this covers any questions you have in terms of weapon controls, if you have any other questions then ask on the Relock forums.