I used those ovulation tests from the supermarket to get pregnant this time around because me and my husband had been trying for 3 months with no success i first tried the one your taking about where it shows a colored line that gets darker when your ovulating i did that test for 2 months and figured out it was impossible too read and i didn't get pregnant either month so i splurged on the digital one the first response digital ovulation test and i ovulated on day 12 i ended up taking a pregnancy test a week and a half later and what do you know 2 lines showed up! I got my positive pregnancy test at 11 days after conception and now I'm 16 weeks so if i were you i definitely spend the extra $20 for the digital it gives you very detailed instructions and if you follow them after you get that"YES" you should be able to conceive within the next 72 hours if not i would consider seeing a fertility specialist.... Hope this helps!
Assuming that your periods are regular. In general most ovulate counting 10 days from the 1st day of your period. (ie. started on the 15th, ovulate 25th). When I tried to get pregnant with my first this is what my doctor advised. No sex until expected ovulation date, and then do it for a week straight. And well it has yet to fail, as I am pregnant with my 5th! Good luck :)