Since you have set up the layout and the stackup, you go to Physical => Analysis and click on "Create a New Analysis", select Resistance Analysis and then check Resistance Network Analysis and click "Next".
In the "Computed Nets" tab you see the each conductive part as a net.
A net includes all the surfaces of the conductive parts that are connected to each other. For example this button which is connected with traces through vias:
3. Once you have selected the net for which you want to get its resistance value, then you zoom in to select the terminals. The terminals are the two curves (or group of curves) that define the source and the sink, that is, the input and output of the current.
So you select a curve and then click on "Add terminal" button at the bottom of the screen:
The terminal is now added in the terminal list shown on the right side:
You do the same for the other side of the conductive part, where the button exists. So, at the end you have one net with two terminals, like this:
The selection of the terminals is very important, because for different terminals you may get very different resistance values, since the current flow may be totally different.
4. Click "Next". Here you may give a name for this analysis and you must select the resources to be used. Resistance Analysis does not require many resources, so in most cases it will be enough to use the lowest option, that is, 8 cores and 16 GB memory.
5. Results are generally available in a couple of minutes. In order to see the resistance value of any net, you simply select it and its resistance value is shown below:
Resistance values depend on the shape of the conductor, the selected terminals, and the sheet resistance of the material as defined in the stackup.
You can also get the resistance network, that includes the resistance values between every node that is included in the route from terminal 1 to terminal 2:
You can download this network as a netlist that can be used in any spice tool as input for spice simulation.