fertilizer isnt about adding this or that intermittently. you may need some adjustments relative to life stage, but in general you should be suppling all of the essential nutes at all times. This is accomplished through slightly different means as far as nutes that are immediately avaialble or ingredients that slowly release nutes over time or need microbes to break it down creating an intermediary step before some of the ingredients can even enter the plant.
5-4-5 won't provide everything, but you are most likely in a soil if using this sort of product, so as long as it compliments the amendments of the soil to add up to a proper ratio of nutes, it'll work well.
These sorts of products need a well-ballanced application with a soil that fills in the gaps well. I see a ton of burnt up plants late flower trying to use this type of thing - outside is a different context and works well because the earth provides what is missing and any overdose is more easily mitigated with shear volume of earth vs potted plant.
Trial and error. If you see someone using exact same soil, you can mimic them and even that may require some adjustments. Just be systematic and improve what you do to avoid any issues each grow cycle and you'll have a good procedure shortly.
at purely a 5-4-5 ratio, it's not something that will fully provide for the plant. Either something will be low or high if it is correct for 1 of the elements. It's meant to supplement wwaht is provided with the soil, and if the soil doesn't match up well, it's going to have symptoms at some point. I'm not trying to scare you away. Just don't think there is a one-size fits all with this product because there are 50 moving parts besides this choice. top-dressing is low effort compared to other options and worth learning. You'll probably experience some bumps in the road along the way.