Add a 10XX block, although counters can be in 04XX, most of the time they will be done in 10XX blocks. Counters count upwards, so they start at 0, and go to infinity (well, fine, not really infinity). Many times you will use counters simply as delay elements, so things don’t keep happening and there are pauses.
First the counter needs to be reset and enabled, by AF and then B1 commands. Then use the command B4 to detect if the counter is greater than a certain value. B5 can also be used to detect if less than a certain value, but generally B4 is more commonly used. In the case below, we check loop until it detects that the counter has exceeded 80, when it does put text on the bottom of the screen, then loop again until the counter has exceeded 180. In this case, we play a sound, then exit the routine.