Welcome to FineTunedMac, elizatyt!

I assume that you are using Safari. Go to the Bookmarks menu and click Show All Bookmarks. Select the the bookmarks that you wish to delete and then press the Delete key. Hint: you can select several bookmarks at the same time by pressing Command while you click. Then, they will all be deleted simultaneously when you press Delete.
As an alternative, you can Control-click (same as Right-click) a bookmark and select Delete from the contextual menu.