The 'yellow sized' terminal crimptool is used to crimp terminals in the gauge 26-22 range. We use the AMP 46121 tool.
Here's a gauge 24 wire that we are going to crimp into a yellow terminal.

The terminal is put in the crimping head of the tool.

The wire can now be inserted into the terminal.

Like the other PIDG terminal crimps, the wire is inserted and the crimp is made.
Make sure that the rear of the terminal firmly grips the insulation for strain relief. (imagine this terminal to be yellow)

picture by: http://aeroelectric.com/

Now that we have made the crimp onto the terminal we can inspect it.

The terminal.

The crimptool can be set to three different tightness settings. 1 being the tightest.
Looking at the strands of wire we can tell wether the tool should be set tighter or looser.

The tightness can be set by moving the pegs to holes 1, 2 or 3.

When crimping terminals, splices or endacps with this tool, Here are some more guidelines.