It's a reboot. Other than what are arguably some loose references/easter eggs to the original game, it has nothing to do with it.
Doom 2 directly follows the original Doom.
Final Doom consists of two ,what would have been fan campaigns, but was bought by id before release and released commercially. Both are setup as alternative sequels to Doom 2.
Doom 3 is a reboot/prequel (seems to depend who you ask, sometimes it's stated as a prequel, other times a reboot). Resurrection Of Evil is an expansion for Doom 3 and directly follows it.
Doom 3 BFG is a rerelease of Doom 3 + the expansions with some tweaked gameplay (opinions differ on if it's better or worse) and graphical tweaks/updates.
Doom (2016) is a reboot.
Other than Resurrection Of Evil, that you should play only after Doom 3, you can pretty much just play in any order you like. The original games are not heavy on story, most of it was in the manual rather than in game and it's practically the same across all the games anyway (UAC dicks around with hell, demons fuck shit up, you fuck the demons up).