It can sometimes be very difficult to know the level of a learner. This is particularly so at high levels. For example, a student who has been learning for a long time might be at one level for listening skills and at another level for vocabulary. Authors and text book writers don’t always agree on levels. If you look at intermediate level course books, you’ll see that they vary greatly in level.
I’m sorry to say, there is no sure fast way of determining the level of a student. The closest you could get to it is public examinations of the type administered by UCLES (Cambridge). You could look at the UCLES website to see if they have a description of levels. Alternatively, you could look at course books that prepare students for FCE, Proficiency, TOEFL, etc.
Another issue is that a text doesn’t correspond to a level. The task you use with the text determines the level. For example, a newspaper article can be used at a variety of levels: if the task is to note down all the nationality adjectives contained in the text, it can be used at an elementary level. If the task is to read and summarise, the level is much higher.
It’s a shame you haven’t given me part of the text you are working on. Without seeing it, I can’t tell you what level it is. As a rule, when doing a reading task you need to pre-teach any vocabulary that is essential to understanding the text. The words you think are essential to understanding should be focussed on and students’ understanding of these words should be checked before they start reading. You can do this in a variety of ways: students match the word with its meaning; they match the word with its opposite; they match the word with a picture…. The pre-teaching of vocabulary should be kept brief; it is not the main focus of the lesson. Pre-teaching vocabulary is important even with advanced students; at higher levels you still focus on the essential words but make the review very brief.
I think you can mention any of the above to your tutors and ask them for some further clarification: what exactly are they looking for in the task? If they clarify, it will help you. By raising the issues mentioned above you can show the tutors that you are thinking about what is involved.