A notebook holds cells of code and their results. Python is the default language. Start a SQL cell with %sql, or change its language with the cell menu. A %md cell contains Markdown notes, not executable SQL. Shift+Enter runs the current cell; Run all executes cells in order, so a later cell can use a table created earlier.
Your training workspace starts in catalog main, schema bronze. A table has a three-part name: catalog, schema, table. Aster Supply's main.bronze.orders contains its raw order feed. Attach compute before running code. An interactive notebook uses notebook compute, while the SQL editor uses a SQL warehouse. This browser keeps execution local and labels those choices for practice. A row count describes the returned result, which can differ from the number of source records.