To create a hyperlink to a specific slide in a different presentation in PowerPoint:

1. Open both presentations in PowerPoint
2. Navigate to the slide you want to hyperlink, in the destination presentation
3. Copy the URL of the slide
4. Navigate to the slide you want to add the hyperlink to, in the source presentation
5. Locate the ‘Insert’ menu and select ‘Hyperlink’
6. Paste the URL into the Address box of the Insert Hyperlink window
7. Click ‘ok’ to add the hyperlink to the slide