Use the below mentioned steps to apply conditional formatting to the cells.
1. Select the cells where you want to apply the Conditional Formatting.
2. Click Conditional Formatting from the top ribbon.
3. Select New Rule.
4. Click Use a formula to determine which cells to format.
5. Enter the below mentioned formula in Format values where this formula is true:
6. You will all the cells which have the word "first aid" in it, the cells against them will be highlighted.
Please revert for clarification.