Is there any way to take my favorite performances alltogether and compile a library that can be loaded afterwords? Or i must take every single favorite performance, save it to user and then compile a library? In that case is there any multiple select so i put in the user category more performances at once?

Yes to all three questions. But totally unnecessary to move a Factory Performance to a Library.

You understand that a Library’s purpose is so that the sound is always available. All Factory Performances are already always available. It would be mismanagement of data to mark a Factory Preset Performance as a Favorite then move it to a Library.

Now if you’ve taken a Factory Preset Performance and edited it in some fashion, you should rename it and Store it (you guessed it, to the User Bank) now there is a reason to place it in a Library.

Since creating a LIBRARY is created by assembling Performances in the USER Bank and then saving a file, you can remove the word “Or” from your question. That is how it is done... assemble the data you want put in your Library into the USER Bank, (there are 640 locations), then
Press [UTILITY]
Touch “Contents” > “Save/Store”
Set Content Type = LIBRARY FILE

You can assemble data into your 640 User from Data already installed as Libraries. Say you want to create a Library to take on the road, where you will be renting a MONTAGE, you would manage your data by using the “Library Import” function.
[UTILITY] > “Comtents” > “Library Import”
Your installed Libraries appear as folders, tap the folder to open it and see a list of the Performances, Place a check mark next to all items you want to import to your User Bank or touch the box “Select All”. Once you assemble everything you want into User create a Library File .X7L.

Why do you want to put Presets in a Library? There is no earthly reason... repetitively redundant. Both Factory Performances and Library Performances are already in ROM.

One reason a musician may want to load copies of factory performances into a library is for a sense of organization and using Libraries as the means to organize. Although the source of these performances wasn't spelled out (factory presets or other libraries). The only clue is that these performances are not already in the user area (which could mean other libraries as much as presets).

The OP may have a preference to using [CATEGORY SEARCH] vs. the [LIVE SET]. In this case, leveraging libraries as an organization means may be OK - although I use [LIVE SET] so my bias would be to leave factory performances alone and point to them with [LIVE SET] (along with pointing to my user performances) as opposed to using libraries. I do this mainly because I'm still tweaking my user performances - so I don't promote them library slots and haven't run out of the 640 slots to require promotion due to space management.

The design concept is to leave the Factory Preset Performances alone, and organize your own listings in a [LIVE SET], since the OP is learning the instrument, best to start with the concept as designed... rather than duplicating Presets, unchanged, to Library locations... no need to do that really, ever... even as a matter of organization.

Even if your preference is to use [CATEGORY SEARCH] vs. [LIVE SET], since anything marked as a Favorite is automatically placed in the Category Search Bank called "Favorite". You can have Favorite Pianos, Favorite Keyboards, Favorite Organs, etc., etc., or you simply Search Favorite All. The actual Performance still exists in whatever Bank they belong to, yet can be 'pulled' together in your own "Favorite” Bank which you view by pressing [CATEGORY SEARCH] twice from the Home screen.

You never have to search through any programs but your Favorites no matter where they actually live.

The concept of creating a Library is that the user can create their own ROM Banks (which will always be available). There is no need to move a Preset Performance to a Library location... where it would now be an exact duplicate (repetitively redundant).

Thank you both for your replies. I was not referring to factory presets. My issue is when i use a third party library and i would like to keep 50 out of 120 presets for instance. Should i place each one of these to user category or there is a multiple select function? (I know there is a multiple select when loading FROM a library but my question is if i can store TO user more than once at the same time. Or there is a workaround to all this?

If you want to select 50 out of 120 Performances you should load the File initially as a LIBRARY FILE. (We'll call this a 'temporary' Library... which we will use to audition the sounds).
Then go to UTILITY > "Contents" > "LIBRARY IMPORT"

Now you can mark your 50 and import them to USER, (using LIBRARY IMPORT), where they can be added to any Performances already in your User Bank.

If you load the data initially to the USER Bank, (firstly this replaces all other data in the User Bank) plus you would have to go through and DELETE 70 Performances from the USER PERFORMANCE Folder. UTILITY > "Contents" > "Data Utility" > Performance Folder.

Finally: once you have all the Performances in your USER Bank, SAVE the data as Library File (.X7L) ... which you now can install permanently...replacing the temporary (audition) Library.

Thanks again , the support in this forum is amazing. I will do it the way you say only drawback that i will have to mark the 50 beforehand but i can live with that