Prerequisite: Launched your first instance from Portal.
Step 1: Navigate to the region that your instance is created.
Note: Security Groups setting differ by region.
Step 2: Go to the Security Groups tab and click Manage Rules to edit your rules.
Step 3: Add a new rule to your Security Group.
Step 4: Set the rule by allowing port(s) according to your use-case.
The specific port will be allowed to connect to your instance from external.