QFT for fermions

This is somewhat a second part of my previous question. On page 18 of Feldman, Trubowitz and Kn√∂rrer’s notes, some aspects of fermionic QFT is introduced and briefly discussed. There, creation and annihilation operators $varphi(x,sigma), varphi^{dagger}(x,sigma)$ are introduced, together with some mention about its time evolution and its thermodynamics counterparts $e^{Htau}varphi(x,sigma)e^{-Htau}, e^{Htau}varphi^{dagger}(x,sigma)e^{-Htau}$. Where can I find a more detailed discussion about this? These are some important objects but I can’t learn much from FTK’s notes since it is a really fast presentation. For instance, it is hard to know what exactly are these operators, their domain (is there an underlying Fock space?) and so on. Thanks so much for your help!