how do I see avif files in 1.4.1 dev version?

[jazei]

hi, I used 1.4.0 flatpack version but It has not support avif format so I tried to install 1.4.1 dev version, I uninstalled flatpack. but now I don't know how to install dev version. I downloaded dev version, then I did command line : sudo dpkg -i XnViewMP-linux-x64.deb and it was installed but whit problems on dependences... but xnview start wel, so I tryed to see avif files but I don't see them...
O.S. Linux mint 21 Vanessa.
screenshot when I try to see avif files:

Regards

[xnview]

avif is not yet supported on linux

[jazei]

avif is not yet supported on linux

OHHH Thank you.
what a lot of details should I see. you are right. seeing viewtopic.php?f=62&t=44522 in the sign of the poster I see that he/she uses Win 10!!!
lots of details to see, and always learning and speaking of learning... a tutorial about installation will be glory. I should use "ddg lite" to learn how install xnview in linux mint.