I've used home covid tests on two occasions, and both times the results were negative. Sometime later, I found out that I had used the tests incorrectly. You are supposed to wait five days after possible exposure before you test!
It's possible that I was actually covid positive but asymptomatic. That's important, because even if you're asymptomatic, you can still spread the virus to other people!
I do a test if I have any symptoms that could possibly be covid. I also did one before attending a party in May. I have not been knowingly exposed to anyone who has covid so I haven't taken one in the situation you describe.
I have a co-worker who was in that situation and he took tests daily after being informed he'd been exposed. He didn't test positive until day 5. On the other hand, I have other coworkers who tested positive a day after arriving home from a company meeting and learning that people they met with had tested positive the day before. All may have been exposed a few days' prior, though.
The test will tell you if you are infected at the time you take it or rather, is likely you are not infected. If you are infected it will pick up the dna. You can do it anytime. Waiting 5 days is strange because you should know if you have caught something by then.I only bother before I mix with others and I also mask and socially distance and disinfect. You can still catch a cold and if for some reason you feel a bit off then test it. Likely is you were not infected and not spreading, and if you also masked and did all other things right you gave nobody anything.Rapid flow Test for travel was 72 hours before.