Struggling with Beams

I'm trying to input the following notation (please see picture) but I can't get it to look similar to the picture. I'm assuming that it has something connected with beaming. I've tried the following
1 putting the 6 notes on the treble clef and then using the "Beam 16th Sub" to create the beam
2. select the first 3 notes and use the shift + ctrl + (downward key) to move them down to the bass clef. So far so good: it's starting to look like the picture. But then problems start occurring.
3 When I try to input the A crotchet note (above the beamed notes on the treble clef), the beamed notes on the bass clef disappears

Also, I can't get my slur to look right. It won't sit where I want it to. I'd appreciate any help that anyone can give me. I'm not a musician but I'm trying to input the musical notation for my son. Also, perhaps what I'm trying to input is not correct musical notation and there's a better way to represent it. If this is the case, please let me know. Thanks in advance