If you are using large sheets or ouarka or phyllo, think about cutting them in half (at least) to shape the triangles or in large strips to make the rolls. Place the ouarka sheet on your work surface shiny side down.
If you are going to fry it, you don't need to brush with butter. If rolls or triangles are going to the oven, then brushing the ouarka sheets with butter is important.
Put a little filling in the bottom of the sheet, a few centimetres from the edge, fold the sides of the sheet over the filling lengthwise making sure the sides are neat and even at all time. (see how to shape a roll).
Fold the strip on itself as you go. Make sure the cheese is trapped inside the wrapping as you don't want it to overflows during frying or baking.
You could seal the last bit of the roll by smearing a bit of flour paste. Place the rolls in the fridge, covered with a cling film until you are ready to fry or bake them.