First, note that the cells in F5:F13 are formatted as Text prior to entry. This allows the times to contain leading zeros like "083000". Alternately, you can enter these time strings with a single quote at the start (') to force Excel to respect them as text.
Next, the time string contains 6 characters in the following format:
hhmmss // as text
This means the formula needs to pick up 2 characters each for hour, minute, and second. Working from the inside out, this task is performed with the LEFT, MID, and RIGHT functions:
LEFT(E5,2) // get hh MID(E5,3,2) // get mm RIGHT(E5,2) // get ss
Each of the functions returns a result directly to the TIME function. In E9, we have:
So the result inside TIME looks like this:
The TIME function then quietly handles the text-to-number conversion and returns a valid time:
Representing 4 hours, 10 minutes, and 55 seconds.
With a 4-character time string
The formula in C5 is meant to handle only a 4 character time string (hours and minutes), so the structure is a bit simpler. We simply hardcode the value for seconds into the TIME function as zero: