Welcome jeneaton1 - we are so pleased you found us. In answer to your questions:
You can scan the books' barcodes into our Import Books feature using a barcode scanner. This is explained in Help, How to, How do I use a barcode scanner to add Books to my Bookshelf?
Alternative spellings is problematic - the example you give isn't even a spelling variation but an alternative name. If you aren't sure of the recipe name, a better way to search is to use the Only show filters on the right. In this case you would select Recipe types; Baking; Brownies, slices & bars and also select lemons from Ingredients; Fruit; Citrus; Lemons. We do have alternative spellings for ingredients so for example if you enter hummus you will also see every recipe using humus, humous, houmous and homos.
I'm not sure what you mean about specifying sources. You can already search just the books you have on your Bookshelf by selecting Bookshelf at the top and left of the screen. You can also add Bookmarks to any of your books or recipes - just click the blue Bookmark button to the right. You can then set up whatever bookmarks you want - locations, favorites, etc. If I didn't understand properly what you meant by selecting Book or Source please can you clarify?
Our Help section does have a lot of explanations (with images) of how the various features on the site work. But if you ever have a question for which you cannot find the answer there, please do post on the Forum or email us at [email protected].