LOL EXT requires some keybinds to work properly, here you can find them.
If you're using a Q, W, E, R keyboard make sure your keys are like these:
https://youtu.be/wvcdFOHvmyI
If you're using an A, Z, E, R keyboard make sure your keys are like these:
https://youtu.be/LHFD6q3_XCk