FILTER(range, condition1, [condition2, ...]) returns the rows of range where every condition is TRUE. A condition is a comparison over a column of the same height, such as C2:C21="Lisbon" or E2:E21>=300.
The result is a list, and it spills: you type the formula in one cell and Sheets fills the cells below and to the right. Click any cell of the result and the formula bar shows the formula in gray, because only the first cell holds it. If something is already in the way, the first cell shows #REF! and hovering it tells you which cell to clear.
Each extra condition narrows the list (this AND that). For this OR that, add the conditions inside one argument: (B2:B21="VIP")+(B2:B21="Speaker"). TRUE counts as 1, so a row passes when the sum is 1 or more.
When no row matches, FILTER returns #N/A with the note "No matches are found in FILTER evaluation." Wrap it in IFNA to show something friendlier.