I think these need some work. Maybe this would work:
1. I have gained valuable experience from leading homework correction (and) discussion sections and from instructing (a) SPSS software operation section for undergraduate students.
does 'for undergrad students' apply to two parts, or only one? because if it applies to both you can rewrite it:
I have gained valuable experience working with undergraduate students leading sections on homework discussion and correction, and on SPSS software operation.
it depends also on the context of the sentence, and what flows best