Automatically open pdf files in adobe reader using the Opera browser

Good day.
I would like to automatically open pdf files in Adobe Reader in the opera browser after clicking the appropriate link under which this file is hidden.
I couldn't find the option in Opera 49, the file is downloaded but not opened. I found the appropriate option in the opera 12 browser, after clicking on the link, the file is opened in Adobre Reader. The problem appears if I connect to a certain internet database (through a browser of course) in which I have pdfs, after clicking pdfa a window pops up asking me if I want to open or save the file. There is an option to "remember the choice", but it is inactive. However, I would like the process to be automatic.
Do you know how to fix this problem so that pdfs will open automatically for me? Best in Opera 49 - probably the newest one.

Go to the properties of any PDF, in the general tab you have "opened with" change it.

Maybe the author managed to set something up, I have been using OPERA recently and has the same problem.
PDF files are saved on the desktop and only another click opens them with adobe ... Mainly it is about shipping labels. Of course, I can choose to open in the browser, but this causes problems with printing (unusual format).
In firefox it worked without a problem, but for some time FF has changed a lot and I am starting to piss me off with its use. Opera, apart from the problem of automatic pdf opening in ADOBE, is very friendly so far.

and I have the opposite problem - I would like to open the pdf file in Acrobat Reader - with the help of a shortcut or link the file is in a network location but I do not know how to