How to link two end of lines?

I’m playing with the app for about a week and bought it today.
Got the problem, that sometimes to end of lines connect magnetically and build (when closed) an object to transform into 3d.
But sometimes, I can zoom as big as I want, but the two ends of the lines do not connect with each other. How can I do this?

Thank you

When you are moving the points of curves, they will snap to specific points, like end points, mid points etc. Just move the end point of a line to another line’s end, that’s it.

No, that does not work always. I tried now. When I start drawing, and stay for a long time at on my starting point (which is another line) it works. but i cannot combine two separate lines.
I could not upload a file, but here is a link to my video:

Those lines are on separate planes. You can’t connect lines that are not on the same plane. Currently we don’t support 3d curves, only planar sketches.

Aaah ok.
Yeah I just saw I messed up my whole sketch. How do I manage on which plane I sketch? Ist it possible to merge two of them?

You can draw on the grid or on faces. Basically where you start drawing, it will define the plane of the sketch. Of you transform a sketch, it will create a new sketch plane of it, or if a sketch plane already exists there, the sketches will be added to that sketch plane. If you double tap on a face, the grid will move onto it, and you can sketch on the entire plane then. Also, if you tap on a sketch item in the groups menu, the grid will move to that sketch.