PDFS/PNGS look blurry when placing in InDesign

The problem could be with the placed AI file.

Questions:

Was the text part of the photo of the building or created separately in AI?

Did you enlarge the image in AI? You can check the image resolution in AI with the Document Info panel:

I wrote an article some time ago

https://creativepro.com/high-res-image-look-low-res/

For the graphic: Save as AI or PDF/X-4 in CMYK, then place it to InDesign.

The photo can be a TIFF, PSD, JPG, separate file, best in RGB with color profile.

Avoid PNG, specially if you produce for printing. Avoid any other PDF than PDF/X-4.

When you create the PDF do it via PDF-Export, no other method.

Take care, that the files are not embedded, but the links have to be available during PDF export.

Welcome to this friendly forum, 
You'd be much better off creating your booklet in InDesign right from the start. In brief, setup your page size, add bleed. Then place your images (with an Effective PPI of around 300PPI) on the pages and there add the text.
Export the document for your printer as a PDF for print - check the requirements with your printer, but probably they will want it as single pages (not spreads) tick Crop Marks and Use Document Bleed Settings.

LinkedIn Learning have step-by-step video tutorials on how to use InDesign in detail. You can get 30-days  free access to all their training. And return here with particular questions if you get stuck.

Have fun!