See the article Introduction To Load Orders for an overview.
LOOT's official version as well as all accompanying files can be downloaded from it's official website or from the Nexus, though the Nexus will exclusively provide the "LOOT.
Installer.exe" executable, which is per se everything you need.
Unofficial "snapshot builds", which are a work in progress and generally used to test future versions of LOOT and provide feedback for wrinklyninja, are made available on Bintray fairly regularly - however this Bintray link should When LOOT is run, it will attempt to detect which of the supported games are installed.If a default game has been set, LOOT will run for it, otherwise it will run for the same game as it last ran for.If the relevant game cannot be detected, or if there is no record of the last game LOOT ran for, it will run for the first detected game. If LOOT cannot detect any supported game installs, it will immediately open the Settings dialog.LOOT is a plugin load order optimiser for TES IV: Oblivion, TES V: Skyrim, Fallout 3, Fallout: New Vegas and Fallout 4.It is designed to assist mod users in avoiding detrimental conflicts, by automatically calculating a load order that satisfies all plugin dependencies and maximises each plugin's impact on the user's game.
LOOT also provides some load order error checking, including checks for requirements, incompatibilities and cyclic dependencies.In addition, it provides a large number of plugin-specific usage notes, bug warnings and Bash Tag suggestions for Wrye Bash.While LOOT is able to calculate correct load order positions for the vast majority of plugins using only their content, it cannot do so for all plugins.As such, LOOT provides a mechanism for supplying additional plugin metadata so that it may sort them correctly.An online masterlist is provided to supply metadata for many plugins that need it, while users can make their own metadata additions, which are saved in their userlist.LOOT is intended to make using mods easier, and mod users should still possess a working knowledge of mod load ordering.