I studied in 2 steps (and this is what I recommend to everyone):
Step 1: Our IBA High-Frequency Word List. Watch both the Bangla and English videos and then learn the words in-depth from our website. As we can see from the website, the same words appear again and again in the IBA exam. So we first have to finish all of these words.
Step 2: After you are done with our word list, then study both Word Smart 1 and 2. A great thing is most of the words from our word list are also in Word Smart 1 and 2. So you will have to learn some extra words from Word Smart 1 and 2.
That's why we are also making videos on Word Smart. Utilize the Word Smart videos.