On the symbology tab of the properties -
For the filter enter "riparian Veg" = 'Yes' AND NOT "Primary" = 'Riparian vegetation management'
capitalization matters - it has to match the field names and attribute values. I just copied what's in your question. If that's not exactly what's in your layer, it won't work.
You use the query builder (the curly E button next to the filter text box) to create this filter with point-and-click. Expand the Fields and Values tree to get your fields. Double-click a field to enter it into the expression. When a field is highlighted, you can click on Values to get a list of the values in the attribute table. Double click a value to enter it into the expression.