Confused, please help!

Hi Ladies, just briefly I have never had regular periods, some times I've had 26-28 days cycle and sometimes 30-40 cycles but quite recently me and partner have decided to TTC (only just learning all these abbreviations!!) so I've been trying to monitor how it all works. I've never been too tuned into my body and have never taken notice of ovulation days or cramps or logged anything down. According to two different apps my ovulation window was from last Thursday to Weds (being yesterday) and every day I took an ovulation test all negative but this morning it was positive, so is this the beginning of my 5 day window or as the egg only last 24hrs will I be showing a negative result tomorrow? When do I have sex? How many days will I be showing a positive result on the ovulation tests? These might be stupid questions to some of you but I genuinely don't know and would appreciate any feedback from you, Thank You K