I don't think there is a manual

there used to be a linux version board on this forum, you can find it here: https://www.talkgraphics.com/forumdi...(forum-closed)

it is a closed forum so you cannot ask there for help but it may be useful to browse through

the program, as I recall was last updated in 2008 - I doubt there are many members here today who actually used the linux version at all, let alone still do; Talkgraphics is now soley for the commercial windows version

crop tool: there isn't one - what you do is draw a shape [or use a quick shape] over your picture - select both shape and picture and use the intersect shapes command [similar to inkscape, but I think terminology may be different]

the key shortcut for intersect shapes is ctrl+3 [or you can use the arrange menu / combine shapes to find it - assuming that it is the same for linux as windows]