Mate with the greatest of respect, cos I know it's all new and muddling, I don't think you understand cycling. It can take WEEKS to cycle a filter, not a few days. It's the process of building up bacteria that convert ammonia into nitrite, then nitrite into nitrate, which you control with water changes. It is a biological process, not a settling in period. You don't cycle a tank, you mature a filter.
25% water changes just aren't going to cut it. Ammonia damages the gills in particular and weakens fish, even when you've got through the cycling fish can seem sickly and just die 'for no reason' - long term damage.
Your shop isn't going to tell you to buy ammonia and do a fishless cycle. It will sell you an inaccurate strip test kit probably, rather than a liquid kit. It'll probably tell you to run the tank for 3 days, maybe a week, and stock slowly, ie landing you right in the middle of a fish in cycle without going into the implications. Then when the fish die, people go to buy more. Maybe they'll even be convinced to buy a bottle of cycling product, which will do NOTHING, or maybe something that clears the water, or removes waste, or purifies it, etc etc. They are a business after all.
Whereas on here the vast majority of us have nothing to gain from giving you advice.