There are number of resources available online. The challenge is to find the right / updated resource . Azure changes its shape and size / evolves every couple of weeks. New features and service offerings are introduced by microsoft very often .
Resource 1: check Microsoft documentation
In this you get tremendous information about azure solutions architect and i suggest to keep a separate favorites folder in your browser to keep track of them . Opt for RSS feeds , that ways you get the latest and greatest information right in your inbox.
Resource 2 : Microsoft virtual academy
This is the Microsoft milky way to provide plethora of training for free. You might wanna search for Microsoft azure in search box and am sure you will find great video based training there.
Resource 3 : YouTube .
I always call youtube as an academy as we can learn anything and everything here . We need to choose the videos wisely though, as some of the videos may be outdated ( based on MS Azure classic ). So check properly and find the right one.
Resource 4 : Professional training
If you are looking for professional training , I have just finished building online, self paced Microsoft Azure Solutions Architect Course that will take you from novice to azure pro.