**EDIT.** I am trying to read the article “Supersymmetry and Morse theory” by E. Witten (JDG 17 (1982)).
This well known article applies some tools developed by physicists (e.g. path integrals) to topology of manifolds.

I am a mathematician, but I am familiar with some necessary physical ideas, although probably on more elementary level than necessary to understand the paper. To be more specific, I cannot understand the computation of matrix elements of the (twisted) de Rham differential $d_t$ on p. 672-673. The exposition there is too concise for me.

Is there a more detailed exposition of Witten’s paper today? However mathematical rigor is not so important for me. I would like to understand the physicists tools and ideas.