A block in a COPP program doesn’t use a BEGIN and an END. Instead of "BEGIN" you use an indentation, while a reverse indentation means "END".
With indents, you create a tree-like structure where the indents show the level structure of the code. The editor inserts vertical lines and highlights the current block that makes it easier to read.
THEN and ELSE are sub-structures to IF and have the same indentation. Plus and minus icons are next to IF, THEN, and ELSE blocks. You can use them to show or hide the block.