Please explain more precisely what you are trying to do. By "put artworks to composers", do you mean embed a specified "composer" image in addition to artist and album cover? If the tag standard allows for that, you can tag/add the composer image easily in MusicBee's tag edit window and also specify you want that one to show up in lieu of other images (the "Primary Picture" option).
Or, if by "artworks" you just mean music files, and you want to tag/sort/display them by composer, you can do that easy (after populating the composer tag) by using the "Set Displayed Fields" and/or the "Define Custom Sorting" options in your Library listing.