What is the test for instructing a jury on the use of circumstantial evidence?

"'It is settled that in criminal cases, even in the absence of a request, the trial court must instruct on the general principles of law relevant to the issues raised by the evidence. [Citations.] The general principles of law governing the case are those principles closely and openly connected with the facts before the court, and which are necessary for the jury's understanding of the case.' [Citations.]" (People v. Diaz (2015) 60 Cal.4th 1176, 1189.) It is not necessary for the trial court to instruct on the use of circumstantial evidence "unless the prosecution substantially relies on circumstantial evidence to prove its case." (People v. Anderson (2001) 25 Cal.4th 543, 582.) "[W]here circumstantial inference is not the primary means by which the prosecution seeks to establish that the defendant engaged in criminal conduct, the instruction may confuse and mislead, and thus should not be given." (Ibid.)