Then it's not obvious that the PSE ACR plugin has two usefull features which can be combined.
- The last set of edits you have just done by clicking 'Done' or 'Open' is saved as 'Previous convesion'.
- The ACR dialog has a menu to access and apply that 'Previous conversion' to selected opened files in the vertical filmstrip on the left. To open this menu, click on the small icon on the right of the 'basic' bar, just under the row of icons.
Knowing that, if you want to apply a conversion which has been applied to a given file, you open that file, click on 'Done' to save its set of edits to the 'Previous conversion' and you apply that conversion to the selected files in the filmstrip.
This means that any set of edits in any converted file may be used as a 'preset' following the above sequence of 'Done' and 'Previous conversion'.
The same menu also lets you apply 'auto' conversion to all opened or selected files.