An option to try to see if it is suitable for your needs:

With PP open, remove everything from the slide for clarity (optional).
Click the View tab, then the Slide Master tab.
Scroll up to the top slide.
Remove everything again for clarity (optional).
Add your content that you want to show on all subsequent slides. This could be Text Boxes, Shapes, Pictures.
You can position them to your requirements.
Now close the Slide Master View.

Save what you have created as a PowerPoint Template in a location of your choice/default location.
Close PP.

Locate the created Template and d/click to open.
You can add additional text/items to slide one should you want to and each additional slide will have all the text/items you added in the Template and you can add further to the slides as you progress.
Note: You can’t move items that were added in the Template unless you open the Slide Master View (Top slide).
Click the image below to see a short video of the above. My example uses PowerPoint 2016.