For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
The form Labels are showing at Top, instead of Left.As troester said you need to overwrite the template. If you don't know how to figure out, nah try using my template and see how it going.