here are links to a few free trapping books. i had these and more as a youngster. A bit dated but the techniques will still work. Note local laws on trapping have changed over the years so for when SHTF or information purposes only. There are others on the same site ...
https://archive.org/details/foxtrapping00hard/page/n10
https://archive.org/details/minktrappingbook00hardrich
https://archive.org/details/amateurtrapperco00hard/page/1
https://archive.org/details/foxtrapping00hard/page/n10
https://archive.org/details/minktrappingbook00hardrich
https://archive.org/details/amateurtrapperco00hard/page/1