To add media to the Timeline, click-and-drag it from the Project bin to the Timeline. A sequence may needed to be created before media can be added (see the Premiere Pro: Timeline & Sequences Overview for more details). 

To rename media, double-click on its name from within the Project panel and type in the new desired name.

Media can be previewed from the Project panel or the Source Monitor. Preview from the Project panel to quickly scrub through a clip to see/hear whats in it, and the Source Monitor to enlarge the clip for finer editing.

To preview from the Project Panel, select the asset in the Project panel and press the Spacebar on the keyboard to play it. Click-and-drag the playhead, which looks like a gray square in the Project panel and indicates the current time position, to scrub through.

To preview in the Source Monitor, double-click the asset from the Project panel and it will then be displayed in the Source Monitor. Use the playback controls located at the bottom of the Source Monitor to preview the asset. The playhead, which looks like a blue pentagon in the Source Monitor, indicates the current time position.

Premiere uses timestamps to indicate the position of playheads. A timestamp is read differently than a clock. From left to right, it reads Hours:Minutes:Seconds:Frames. The time above is 23 minutes, 27 seconds, and 11 frames. The number of frames per second may vary depending on what the recording settings on the camera were, but will likely be 24, 30, or 60 frames per second.

In the Source Monitor, the timestamp to the lower-left shows the time of the current playhead location, and the timestamp to the lower-right shows the total length of the asset.

Use bins, which act as folders, to organize files in the Project panel. Organize resources in a way that will make sense to you and make your own workflow easier, for example by type, date, or scene.