If you have a grounding of networking basics, navigating the dashboard is the biggest hurdle you'll face.
Once you get accustomed to it, you'll find most things logically.
There's a few Youtube videos which provide a good overview of the dashboard and how to use it.
Meraki Dashboard 101: Onboarding - YouTube
Cisco Meraki Dashboard overview demonstration - YouTube
Beyond that, I recommend taking some time to get used to where things are laid out in the dashboard.
This is especially necessary for firewall rules/ACL's as there's different places where these can be added.
Also get to know Network Wide settings and Organisation Wide settings - they're typically where you'll spend the least amount of time, but do hold some key settings that you'll likely need at a later time.
Then when you have a good idea of the specific task you're trying to achieve, the Meraki documentation is typically quite good (Google usually gets you to the right place).