See the link below for reassembly.
go on the computer and scan the words 'marksman air pistol' ...............
See the attached Link: https://www.youtube.com/watch?v=H5qbEgnSZF0
which Model are you asking about
To get an answer you will have to state the condition of the pistol & is it still working?
Starting in 1977 to present
Marksman doesn't list the cocking effort but believe me it's very little. The pistol only fires a 220 FPS and that is slow.
200 Feet Per Second (FPS)
There's a double action to the slide - see the link below for a manual:
Marksman made several models. Which one are you asking about.,
somewhere around $30
marksman