Example ANOVAs from Stata
The best way to get comfortable/familiar with Stata's ANOVA command is to run ANOVAs using various methods and see what the results look like. In the Stata Reference Manual (known as [R]) there are examples of everything from basic single-factor ANOVAs to complex nested ones. If you don't happen to have any data handy, follow the instructions below.
First, make sure any data you have open is saved by typing save, replace into the Command window. If you are not certain if you have made changes, or about what those changes are, you might want to say save [useful title for your data with identifier] which will cause Stata to save a new(er) version of your data with the new title. Once you have saved type clear
Now you can load Stata's datasets. The easiest way to see samples and examples is to type help anova
Doing this will display Stata's official help for the anova command. One aspect of this help file is a series of examples using Stata's readymade datasets. These can be a nice way to get used to commands before running them on your own data sets. Example data also exists on the help pages for other statistical tests, like t-tests and correlations.