Welcome! 
A good place to begin is the “get started” list in the project reports section of the quick browse lists in the community – created wiki. Many different topics there which should be of particular interest to newcomers, so you should find lots of ideas and inspiration.
http://thingsthataresmart.wiki/index.php?title=How_to_Quick_Browse_the_Community-Created_SmartApps_Forum_Section#Quick_Browse_Links_for_Project_Reports.2FQuestions
As far as your other zwave devices, the SmartThings hub does include a certified Z wave controller. That means that most other certified zwave devices should be able to work with it for at least a basic on/off/dim function. If the device has advanced features, it may require a custom “device type handler” to access the advanced features, but more on that later. 
When moving a Z wave device from one controller to another you basically have to go through two steps.
First, you have to get the device to forget that it used to belong to the other controller. This process is called “Z wave exclusion.”
Second, you add it to the new controller. This process is called “zwave inclusion.”
Zwave Exclusion
Z wave exclusion requires that the device erase its internal memory of the old controller. This is different than just deleting it from the network or even resetting it. Z wave devices are intended to be stubborn about holding onto their controller information so that you don’t have to continually re-add it to the network. This is why you can reset all the parameters on a device, but still have it belong to its current network.
Anyway, in order to complete the exclusion, any Z wave controller, including your SmartThings hub, can issue an exclude command which will be heard by all powered on nearby Z wave devices, whether they belong to its network already or not.
Then there will be some kind of physical manipulation pattern that you perform on the end device itself, typically something like pressing a button three times, and then that individual device will go ahead and clear its memory of its last network controller.
So in order to get your old dlink zwave devices ready to join your smartthings hub, you need to dig out the manuals or find them online and find out how each individual model is excluded from a Z wave network. Like I said, it’s typically some button press pattern.
Once you have that information, you have the smartthings hub issue a general exclude, you perform the manipulation on the device that you are trying to clear, and then it should be ready to add just like it was a brand new device.
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You can use the same method for any certified Z wave device. In fact, if you buy a brand new device and you are having trouble getting it to join the network, The first troubleshooting step is to do a general exclude, just in case it was paired to a test network at the factory and the information wasn’t properly cleared before it was released for sale.
You might also need to do a general exclude if you started pairing a Device and for some reason the pairing failed in the middle and you needed to start over.
It’s similar to a factory reset, except that in this case what we are resetting is just the specific information about which network controller this device should be reporting to.
Zwave Include
Once you have completed the general exclude, you are now ready to add the device just like it was a brand new device.
Again, there will be two steps to this. Begin by finding the manual for the device and read the instructions for how it is included to a new network. And again, this usually involves some button press pattern, which might be exactly the same pattern as the one for exclusion.
And again, you will start by having the SmartThings hub issue the inclusion command, in this case with the “add a thing” option in the SmartThings mobile app, and then you will do some kind of physical manipulation on the device to get it to accept the command and join your SmartThings network.
A note about the S2 framework
Beginning with April 2017, the Z wave alliance added some new security features, which will eventually allow devices certified after that date to be added just by scanning a QR code. However, that option will not be retroactive for older devices, and it’s not available on most zwave devices now. But eventually the zwave exclusion/inclusion process may be quite different than what I have described above.
But as of this writing, October 2017, all your Z wave devices should require the same two-step process: issue a command from the SmartThings hub, then do something physically with the device, typically a button press pattern, to accept that command.
And as of this writing, if you have a device that used to belong to a different Z wave network, you will have to go through the exclusion process before you can add it to a new network.
I hope that helps. The Dlink zwave Devices are quite nice, I wish they would sell them on the US frequency as well.
