in most cases is a tool icon that looks like a rectangle made with dashed lines. Slecting it and then putting the cursor toward the upper-left corner of where you can left-click and drag the cursor to the lower-right, thereby framinging your obejcts in the dashed-line box that appears. Once the box is sized correctly, release the left button and select "crop" from what is probably under the "image" or "edit" menu.

This is the typical process. However, the "crop" cursor may also be achieved by clicking an icon that looks like an "L" "7" image, where all the legs over-lap to appear like a sizable box. (Sorry I can't post images of these icons from here.) But the "crop" cursor basically works the same way to draw a box around what you want to keep and trims off everything outside the box.

I'm sure you will find this out by playing around with the controls.

Jim