There is no shortage of study material found on the internet. Just sit down and search on google. One such site is the MIT OpenCourseWare. You can follow the entire ground school for PPL, including slides and video recordings. The course follows the American syllabus that we know is not as thorough as the European syllabus, but most subjects are the same. There are some differences in the chapter Air Law, so maybe you’d better avoid it. To keep track of what’s covered in the other subjects, keep an eye on the EASA syllabus as you watch the videos or review the slides. You can download the entire course offline and have it with you everywhere. Otherwise, you can find it all on the links below.
MIT PPL course
American textbooks theory and practical
EASA Syllabus