@ Sebastian Omana,
You will find the order of the lessons (from easy to difficult) on my website www.anglo-link.com
To be able to access the lessons, you must first register as a Standard Member. This is free. After registration, click on 'Exercises' in the top menu bar.
The first 4 (101 - 104) sections cover the Elementary level. The next 7 sections (105 - 111) cover the Intermediate level. The last 6 sections (112 - 117) cover the Advanced level.