Graph editor can help you to change the rotation speed and the degree of rotation. It is in the corner of the composition panel on the right hand side.
To get into the exact spot of footage, in the control panel below the composition screen there is a tab showing time. On double clicking the tab, it will open a window where you can adjust the time and you can reach to the exact spot of the footage.
The mask is the technique by which you can select the specific area within the image or picture you want to modify while leaving the rest of the image steady, the short key to select image in mask is Ctrl+T.
There are three axis x, y and z that your picture can rotate and to select the axis, you have to click on the right side of one of the three boxes that resides right below the “Tool bar”. The “Tool bar” is between the “Source Name” bar and “Parent” bar in the composition panel.