The left panel contains the inspectors and track visibility options.
The first tab is the track inspector, which shows various options about the selected track.
See Track Inspector for more details.
The plugin inspector shows various options for the selected plugin.
The plugin properties show the name and type of the plugin, as well as preset and bank selectors.
These are the ports that the plugin has.
Control input ports can be changed by clicking and dragging, and can also be automated using automation tracks. Ports can be routed to other ports anywhere within Zrythm by double clicking on them.
Ports are explained in more detail in Ports.
Depending on the type of plugin, there may be different categories of ports being shown.