When you do a square, you repeat the mantra of the working as many times as it's written on the current square you're in. Example: You start a Mars Square, the day you start it you repeat the mantra 15 times (the number on the first square indicated by the start). The next day you do the repetitions on the next square, which is 2, and so on until you finish the square.
The same applies to any working you have started. Squares a bit special in that the repetitions change each day due to numerology reasons, but a regular working will usually consist of you vibrating a rune or a mantra a certain number of repetitions every day consistently without change.
Now, I'm not sure if you can "repeat" the working. Some rituals, like the RTR can be "spammed" as many times as you want in a day, but I don't know if that applies to regular workings as well. Someone who knows more will probably give you a more comprehensive answer. Hope this helps.