The way which you should hold them
Original: the way which you should hold them
It's not "wrong" per se, but it is non-preferred.
"You should hold them" is a restrictive relative clause (essential, no commas). "That" should be used for restrictive relative clauses. "Which" should be used for nonrestrictive relative clauses. A web search will tell you this.
=> the way THAT you should hold them (in this structure, "that" can be omitted without loss of meaning)
One reference: https://writingcenter.unc.edu/tips-and-tools/relative-clauses/