How do I access the hot spot on an IPhone 5

settings, general, cellular, set up personal hotspot.

If you're referring to Personal Hotspot, on iOS 6.1 it is in Settings > General > Personal Hotspot or burried deeper where iinami already posted. Be aware though that not all operators allow Personal Hotspot without paying for an additional data sharing package so you may or may not have it accessible.

Here are some links that will help:

Understanding Personal Hotspot

System requirements for Personal Hotspot

Troubleshooting Personal Hotspot