The MIDI tracks in ProTools are similar to the Audio Tracks in that you can edit them with some similar receptual controls. You can edit volume, panning, and other parameters or a MIDI "performance" after the fact, and polish up your MIDI.
The controls are the same as the ones you use for audio. You use the hand tool to grab a note, the strip tool to shorten or lengthen it. The hand tool can be used to select a group of note events--it should look like a crosshairs when it is positioned over any part of the MIDI track that is not a note (blank).
We'll talk more about editing MIDI in Spring. You can look in the MIDI menu to see some of the processes that are available, but for now, Tempo and Meter changes should be the only things you need.