I would start with the simple things first. (1) do you have a fully charged battery and (2) do you have good ground from the engine thru the body and back to the battery?
I used to do road service calls and threw a new battery and rebuilt starter at no-start Isuzu diesel pickup. On the 3rd visit,I found a loose ground at the engine block after I fixed that, I never heard from them again


1986 Dodge Ramcharger 440 2wd, Bracket Racer Under Construction
1998 Ram 2500 QuadCab, new daily driver.
2008 Honda Element
2014 Carry-On 7x14 Cargo Trailer