Click on the hammer and sickle spanner button on the right of the screen.

Click the hammer and commie sickle spanner again, the first icon on the top left.

This is the list of levels you have saved.
Notice how all of them are noob levels or just hopping on bandwagons. We are about to fix all of this right now so you can someday get the icon for 50, 100 and star-rated levels.
Click the purple 'new' circle on the bottom right.

The naming of the level is very important. I couldn't think of a cool name, but I'm sure you can settle for a mathematical shape that is misspelled a tiny bit... like 'Leminscate' (OH SNAP!!!)
Once you are done with that, click the hammer and spanner again.

Ok so this is the level preview screen.



This part is complicated, but bear with me. What you have to do now is select the black square at the top left of the 'Build' tab selected. Don't worry about all those other buttons (so do what you already do ( ͡° ͜ʖ ͡°) )

After that, click anywhere on the level.



We did it reddit!!!

Now click the pause button and then click 'Save and Play'.
Prepare for the incredible work of God that you are about to see.

This is what your level should look like now.










Just take my word for it. Now you're the master of playing levels and creating them.
Good luck ( ͡° ͜ʖ ͡°)