This is a video guide to the Explore Trophy:
It takes 10-15 mins to do.
You need to be in the desert area after the large bridge (also reachable as the first choice in the chapter select hub.
There are 7 creature areas you need to unlock - I'm referring to them in the order in the video.
1st - straight in front of the starting area
2nd - forward and slightly to the right of the 1st
3rd - go right, over the Mirage Flower and continue directly away from the mountain. Quite a distance away is a small set of ruined columns and the creature is in front of those. There is a hidden symbol on top of one of the columns here also.
4th - coming back over the mirage flower, go past the hidden glyph and take a left at the three stones in a row going up a dune. You will come to a tower with a ruined building. The creature is next to the ruined building
5th - with the previous creature area behind you, turn right and head over the dune (there should be a pod of the larger cloth creature (dolphins) waiting nearby. You should see another hidden glyph a short distance away. The creature is waiting to be released just beyond that glyph
6th - from the tower area with the 4th creature just head towards the tower. In fact you should be able to head towards the mountain anywhere in the desert to reach this area - a large tower. As you start on climb this, you'll pass these in the smaller part of the tower. I think you may need to do this one to get the boost up.
7th (and final) - Once you have made it to the top of the tower and used the standing stone, the grate will up and a pod of dolphin cloths will be released. You can't miss this one and continue.
I haven't checked but I think you may need to release a number of the other pods as well in other to get the boost to climb the tower. It's the 3rd and 5th area's that you are most likely to miss.