Exploits are entry points which allow further homebrew to be run. In the main guide, you will use exploits such as the browser exploit (http://wiiuexploit.xyz) and PayloadLoader (Health & Safety exploit). All current exploits load `SD:/wiiu/payload.elf` which takes over further loading of homebrew.
Payloads, which are normally found with the filename `payload.elf`, exist to make it easier to have different exploits load the same next stage, which allows easier updateability. It doesn't matter what exploit loads the payload, the result is always the same. Multiple payloads can be switched between using the PayloadLoaderPayload. The payload used in the main guide is CustomRPXLoader which loads `SD:/wiiu/payload.rpx` and the `payload.rpx` used in the guide is EnvironmentLoader, which allows you to load different environments.
An environment is a collection of "setup modules", which will be run in a certain order when launching the environment. Such environments are Aroma and Tiramisu. Setup modules are small pieces of homebrew/code that are executed once to set up an environment.
No, you must have an SD Card for a first time setup. A USB can then be used to install game backups, Virtual Console injects, etc, but not to store homebrew applications which are required to set everything up.
你自己看着整吧,无论是把它们留在原处、删除它们或者替换它们为新的什么的等等都由你自己摆布。 Those files are not used in the process, and therefore, won't have any impact by being or not being there.