Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.0.35.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 17
where the (Link ID) Network/subnet number should be 10.0.35.0 and not 10.0.15.0.
I will let Rene know to change that.
The /24 in the label of that DR just indicates that this DR is performing its function for a point to point link, that is, a single /24 subnet. This is stated later on in the lesson as shown:
I suggest you take a look at the following lesson about LSAs. It presents areas from the point of view of LSAs, which may be helpful in clarifying the functionality of each.
In your reading, if you do have any questions or you need any clarification, feel free to ask.