All the web pages that are saved as Bookmark can be accessed from within the Bookmarks menu. You can also open the bookmark in a window (menu item Bookmarks > Manage Bookmarks) where you can edit, delete, reorder then and create new folders to organize the bookmarks.
You can even mark a certain folder as "Favorites" folder. All bookmarks in this folder will be shown in the Favorites toolbar of each browser window, so these bookmarks can be accessed much faster than any others.
Normal bookmarks represent single web site. But there is also a special type of bookmark which is called Tab Group which can be used to save any number of web sites which are displayed as Tabs in a window. This can be useful to save a group of related web sites as a unit which can all be opened at the same time as Tabs again.
BTW: the bookmarks icon of the toolbar shows and additional "star" if the current web site is already available as bookmark, so you can immediately see if it makes sense to bookmark the page again.
You can create folders in the bookmarks window, to group bookmarks by topic. This can be done either by using the buttons in the toolbar or using the contextual menu.
Double-clicking a folder in the bookmarks window will open this folder in a new window. This makes it easy if you want to move bookmarks from one folder into another, because you can have both folders in separate windows so you can drag and drop the bookmarks without the need to scroll.
To sort the bookmarks alphabetically, just click the column header buttons at the top of the bookmarks window. This will sort the items in the current folder. Subfolders won't be sorted, you can sort them by opening the folder in a new window first and click the column header in this window.
You can also use drag & drop to reorder bookmark items manually.
Each modification (deleting items, creating items, sorting, reordering etc.) can be undone. Just select the menu item Edit > Undo.
There are several ways to edit the data of a bookmark. You can select the bookmark you want to edit and then click the Information button in the toolbar. This will open a dialog box where you can edit all the data of the selected bookmark. But you can also edit the URL, title and description inline directly in the bookmarks list of the bookmarks window. To do this first select the bookmark, wait a short time and then click again on the title, URL or description which will then activate the inline editing feature.
To change the Favorites folder just select a folder and then click the Set Favorites button in the toolbar (or using the same option from the contextual menu).
It's also possible to export bookmarks using the menu item Bookmarks > Export which can be then imported in any other browser again.
An alternative for synchronizing the bookmarks with multiple computers and also with iCab Mobile on the iOS platform would be the "iCloud". In the iCloud settings you can enable the iCloud sync for the bookmarks. This way you can also sync the bookmarks between icab on the Mac and iCab Mobile on iPad and iPhone.