There're 2 ways to do so:
(1) Download book files from the bookstore's website on your computer. Please note that the book files must be in EPUB or PDF format;
(2) Transfer the ebook files from your computer to the SD card/internal storage of your device;
(3) Launch the Aldiko Book Reader, tap on the navigation drawer indicator icon at the top left and then select "Files";
(4) Locate the ebook files that you just transferred. Check the box next to the ebook files and then select the "import" icon (the downward arrow inside a square).
(1) Open Aldiko Book Reader, tap on the navigation drawer indicator icon at the top left and then select "Other catalogs".
(2) Tap on "MY CATALOGS", select "Add a catalog", and then enter the title and web link of the bookstore catalog that you would like to add, click "OK".
(3) You can tap on the store name, download books from the store's website inside Aldiko Book Reader directly.