A variable holds a value that the flow can change as it runs. Create it with Initialize variable at the top level of the flow, change it with Set variable wherever it's decided, such as in each branch of a condition, and read it with variables('Name').
Filter array keeps the items of an array that match a condition and drops the rest. Give it the array in From, and a condition that uses item(), the item being checked. The example drops one person's email from a list of approvers.
Select builds a new array from an existing one, one item for each. To keep just one field of each object, such as each person's email, switch Map to text mode and enter item()?['Email']. The result is a plain list of emails, with no loop.
SharePoint's Get item reads one item from a list by its ID. Give it the site, the list and the ID, and every column of that item becomes dynamic content for the rest of the flow. The ID often comes from another item, such as a department's ID stored on an overtime entry.
length() returns how many items an array has. Put it in a Condition, length(...) is greater than 0, and the flow takes one branch when the array has items and the other when it's empty.
A trigger condition lets a flow start only when an expression is true. Add it in the trigger's Settings, under Trigger conditions, as an expression that starts with @. It's also how a flow that updates the item it was triggered by avoids starting itself again.
A flow in a solution shouldn't have a fixed SharePoint site and list: in the next environment, they're different. Put environment variables in the fields instead. In the new designer, choose Enter custom value, open the dynamic content list, and pick the variable; it's listed under Parameters.
SharePoint's When an item is created or modified trigger starts a flow each time an item is added to a list or changed. Give it the site and the list, and every column of the item becomes something the flow can use. It isn't instant: in my tests, the flow started about a minute after each save.
An automated cloud flow runs by itself when something happens, such as an item being added to a SharePoint list. Create it inside a solution with New > Automation > Cloud flow > Automated, give it a name and a trigger, and add one action before you save it.
A new flow I created inside a solution connected its SharePoint trigger to a connection reference from another solution in the same environment, and its own solution had no connection reference at all. Power Automate does this on purpose: it reuses an existing reference before it creates one. Creating a SharePoint connection reference in the solution and switching each action to it kept everything the flow needs in its own solution.
