This package uses command line tool ghdl and gtkwave software (both are free) to compile and run VHDL codes directly from atom. You'll need to install both softwares to get the best out of the plugin.
Pressing f8 runs a compilation of the current file. Pressing f9 runs a compilation of the current file, the last testbench used, and then runs the code, opening the resulting signals on gtkWave. Pressing f10 opens a dialog that lets you select a new testbench for the current file or run the code with the last one.
If there's not a previous selected testbench, it automatically assumes that your testbench is named as the main code's file, with a _tb after the name
Example: Main file: ANDgate.vhd TB file: ANDgate_tb.vhd
Warning! Code will run successfuly if you use the run commands by having main pane window as active pane.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.