How do you stop stems from connecting?

I have been having an issue regarding stems automatically connecting, and can't figure out how to stop it.

What it is supposed to look like:
http://i.imgur.com/vFXiuse.jpg

What it ends up looking like:
http://i.imgur.com/WmVhQeC.jpg

How do I stop this from happening?

Also, I am trying to add pair of quavers above a pair of crotchets, but that gives me a similar problem.

What it is supposed to look like:
http://i.imgur.com/bGPheqq.jpg

What it ends up looking like:
http://i.imgur.com/C5Pn9EX.jpg

I have tried to figure out how to stop this from happening for about an hour or so now, and can't figure it out. It doesn't matter what order I input them in, or which notes I use, they always end up looking something like that.