Janet Smith

Is your Publisher Document set to 300 dpi?
Before you export the file go to File > Document Setup... and in the Layout tab check and see what the dpi is set to, if necessary change it to 300.

Welcome to the Forums @Janet Smith😊  The Betas for Photo, Designer, and Publisher are all in the Release Candidate phase at this point, and it will probably be relatively soon when they will be available as upgrades to version 1.8.+.   (They do need to be issued together, in order for the wonderful feature of StudioLink to function properly.)  Until that point, anything that you create using the Beta for Publisher could conceivably have problems that could potentially reflect upon your work.  If you need to do anything in Publisher right now that has real-world consequences, it would be a good idea to use your trial version of Publisher.   You can always save a file, and open it in the Beta and see how you fare!  If it is issue-free then you are ahead.  If it has glitches, you will not have done all that work in vain.   It can be the case that something created using a Beta is not backwards compatible to a release version.  So you will want to think of that too.  Hopefully, long before your free trial of Publisher has expired, Publisher v. 1.9.+ will be available for us all!   Hope this helps!    

It’s a customer beta, so it is indeed true that you need to buy the retail version before you can access it. If you purchase from the Affinity Store you’re covered by a 14-day ‘no quibble’ money back guarantee, so that would be a way of having a trial play with Data Merge.

The 1.9 beta should be released quite soon, probably weeks not months.
I have found that the Data Merge works quite well, just make sure you have the fields you really need in the CSV file and all should be good. There are some problems with XLSX (?) files having cells with complex formulas causing problems so I have gotten in the habit of exporting CSV files. As far as I can tell images need to be in the same folder as the CSV file for them to be imported, I could be wrong.
Final Caveat: Affinity files do not play well with cloud services and some networked drive systems.

Somebody please correct me if I am mistaken, but it was my understanding that you would be able to have a new trial period with release 1.9 when it finally comes out.
Edit: my fellow members have helpfully pointed out that I was mistaken. Sorry.

That’s what I used to think, Garrett, but it seems that it ain’t necessarily so!
 

We do not know how quickly Serif will update the free trial to 1.9, though. It is likely to remain 1.8 for some period of time before they make that change.