How Do I Begin?

It’s up to you! You could begin by pointing-and-clicking your way through Configuring the Salesforce App and working all the way through Using Actions in the Salesforce App. Then, put your developer hat on and create custom actions or add canvas apps to further enhance your users’ Salesforce experience.

If you’re a seasoned developer, you could jump into the deep end first with the Welcome to Salesforce Platform Development chapter.