Here are the missing instructions – ChromoFill L Free Color Crosswords Review

I figured out how to play this. I have no idea why the dev didn't include that somewhere. The patterns you select from are for both across and down, without a hint as to the correct orientation. That's typical for this kind of puzzle. One suggestion to the dev is to put some breaks between the patterns of different lengths, as well as a thin border around the patterns. However, often this kind of puzzle comes with one segment already correctly place, or some unique arrangement which makes beginning these puzzles much easier. To start the puzzles in this app, sadly, you do have to guess blindly. I suggest selecting a five long patterns and the click every square that starts a five long section, either across or down. Once you have found the correct placement, the crossword part starts. The pattern you just placed shares squares with empty sections. The patterns which fill these sections will have the same color in the shared square. So check the length of the section, and note the shared square's color and position in the empty section. The pattern which belongs in the empty section will have that color in that position. Try all such patterns. Note that the left to right sequence of the patterns will run either left to right or top to bottom somewhere in the grid. The more squares which are filled in in a section, the easier it is to determine the correct pattern. Also note that nothing appears to happen when you complete the puzzle.
Review by Jack Burton, ME! on ChromoFill L Free Color Crosswords.