You're on the right track with your comment about if you're both on the same frequency you should be able to communicate, but there's way more to it. You're also on the right track with your comment about programming a scanner being similar to programming your dual band radios, but also there's way more to it. Check the band plan at the link above, but you can ignore most of that information for now. Just look over two sections, the "2 Meters (144-148 MHz)" and the "70 Centimeters (420-450 MHz)" sections. The rest will have nothing to do with the radios you have selected. Skip the parts that don't say "Simplex", "Repeater Inputs", or "Repeater Outputs". Also skip the part that mentions "packet" since you won't be using that at this point.
One important point is to listen (for quite a while!!!) before you talk. That will teach you how the local users act on the bands and how you should probably act also. Be aware, however, that there are some areas that regularly have bad actors (think profanity and topics that may not be appropriate for a wide audience) and don't copy that bad behavior.
Simplex frequencies are where your receive and transmit frequencies are the same. This is the most basic operation but will have really short range. You'll also need to make sure that nobody is currently using that frequency for their conversation. Be aware that you may not hear both sides of that conversation so listen for several minutes to make sure you don't interfere with them.
Repeaters you will be transmitting on one frequency and receiving on another and going through a third device that will translate where you transmit to the associated receive frequency (sounds complex, but basically it will increase your range by a whole lot so it's worth it). Also note that use of a repeater is at the pleasure of the repeater owner, but in most cases so long as you follow their rules they encourage folks to use them. Repeaters are often (but not always) owned by a radio club and most will have a web site that will list their repeaters, the correct settings for those repeaters, and what, if any, restrictions exist for their use. In most cases, the restrictions are not going to be a problem and simply be things like "This repeater is the xxxxx County SkyWarn primary repeater" or be a list of scheduled nets and you will likely be allowed to use the repeater for normal "ham" conversations when that repeater isn't being used for SkyWarn or a scheduled net. If you have questions about their use, attend one of the club's meetings or use their contact page to ask your questions. Also be aware that setting up and running a repeater can be rather expensive so if you often use a repeater, you probably should join the club to help support it financially through your dues (generally not a large amount).
This is a very basic starting point, but should get you started. There are many more topics, such as "tones" and frequencies (such as those used for linking repeaters or specialty modes but if you skipped what lines I indicated in the first paragraph, you should be good here) that typically should be avoided (these are often specific to the area, repeater, etc.) and beyond a "getting started" post. A local ham club should be a good resource to help with the specifics in your area, and may even have folks that will be happy to help program your radios for you and teach you how to use them. Good luck and enjoy the hobby!