Lessons are comprised of blocks of content, blocks can be anything from pure Content to auto marked free response questions.
1. From your lesson, click "Add block"
2. Select one of the block types, in this example we'll go for a Content block.
3. To delete a block, simply click on the trash icon.
4. Click "Delete"
5. Click "Delete"
Alert: Don't forget that once deleted content blocks cannot be recovered, so please use this feature with care.