Use the red and green bar on either end of the CTI to create a selection.
Once a selection is made, you can click the Spacebar to PLAY or PAUSE the selection. Click the spacebar repeatedly to REPLAY the selection.
Press SHIFT + , or SHIFT + . to increase or decrease the selection. Pressing the period (.) or comma (,) by itself will increase or decrease the frame number when the play head is selected.
Double-click on the CTI to return the red and green bars and to release the selection.
If you want to do a clip selection instead of a timeline selection, hold down the CMD key (Mac) or the CTRL key (PC) and drag out a selection across the clip. CAUTION: If you click the timeline, it will convert back to a timeline selection.