The error message is trying to tell you that you need to connect a Solver Configuration block to the Simscape network you have built. Once you have done that, then you will be able to simulate.
There is a tutorial in the Simscape documentation that takes you step-by-step through building a model, including ways to plot results using the Simscape Results Explorer . I really recommend going through it, for it shows you many tips and tricks that will accelerate your work.
Thanks,
--Steve