2000 Dodge Ram, Compustar CS4900s

Hi, first of all, thank you for keeping this site going. Its helped me so much over the last 20 or so years. I used to love coming here just to read the articles of how electronics work. Ive done plenty of car audio in my time but this is one thing i've always thought was above my head. i have a 2000 dodge ram diesel and was looking to get a compustar CS4900s. As simple as this truck is i think i would like to attempt this install myself. I've found the wiring information here and looks pretty straight forward but there are things that always confused me in alarm installs. like relays, resistors and diodes. I know how those all work but don't know when and where to use them. Only thing i saw mentioned in the diagram is that it would require a 1500ohm resistor to disarm the factory alarm and a relay for remote start. The resistor i assume will just be inline with the wire going to the CS but no clue on the relay or any other components that might be needed. Any help would be greatly appreciated. Thank you

also, i found a site where they mention that this truck uses a "5 wire" lock system which would require wiring in 2 relays. how would i know if this is needed or not?