Before you do anything, you should go into the options>change keys and set them to one's that make it comfortable.

Then you should mess with the offset to line up the music with your playing. This will take multiple tries. The best way to start figuring out the offset is the fail a song while typing to the beat. There will be a recommended offset at the bottom. This will still need adjusting.
It is also possible that the recommended offset could be too small. I personally had to set mine at over 400ms.

After those adjustments, you should be good to start your LEZ journey! Have fun!

There are currently a few ways for you to boost your score using mods.

If you're having trouble with a song because the notes are too fast, go into the mods at the center-bottom of the screen and slow down the notes. While it does decrease you're score multiplier, hitting more notes and getting higher combos will end up giving you a better score. This also let's you get used to the song so you can speed it up later.

If you're already confident in the song, you could do a few things.

If you almost have a full combo, then you should slow down the notes to 0.75% and put insta death on. It might take a few tries, but it gives you a 1.5x multiplier as well as a full combo.

If you can't get full combo but you're confident in at least most the song, I recommend speeding up the notes. If you can keep up, it'll increase your score. If not, it's good practice for those tricky parts and they'll seem easier when you do normal speed.

If you both speed up the song and have insta-death on, you can have up to a 2.25x multiplier. It's a high risk high reward scenario.

These are all the available ranked mods right now. Go have fun!

Currently LEZ isn't fully finished. I'll hopefully be updating this as LEZ continues to update and add more things.