Good product, but read the instruction reviews so you know how to put it together without breaking a piece of plastic inadevertently.
Firstly, the main instruction page seems to be on page 2. The first “clamp page” is only relevant if you are going to attach it (which is an additional part) to an above ground pool. Otherwise only one page is relevant.
The device comes assembled for transport, and needs to have the “top” part disassembled. This is the hardest part. Take your time. Be in a calm and unhurried mood. It needs a small to medium flat head screwdriver (get a feel for what size is right - Goldilocks principle needed - not too big, not too small) with two pieces of electrical tape applied to the end. Lengthways. The tape will overlap eitherside of the screwdriver head, but that is helpful as it allows a sliding into to gap. The Aqualevel top should be turned upside down and the two plastic overlaps at the widest part noted. Come at one of these with the taped screwdriver from the longer end, gently shimmy and edge along this gap whilst getting a feel for the overlap to come loose. Slowly, slowly, it will need only 2mm or so to spread, but do not be rough. It will eventually give way, and with that the overlap on the other wide side will come free easily. The after that the two overlaps at the hose end will come free very easily.
Look at the parts and pretend to put them together without actually doing so. Consider finding 4 flattish smooth stones to…