It sounds like you are entering notes in notation mode and they are sounding choppy when you play them back. If this is the case, try changing the duration of the entered note. To do this, when in Notation Mode, follow the 1, 2, 3 below. As you can see, I set my duration to 98%. See if this helps.
The answers here underline a really good new feature in the 2016 version.
Being a trombone player, I always go for a legato sound in the melodies I enter. I actually have my 'Duration %' set at 100% in the screen Noel illustrates. So I wondered why it would be necessary to introduce the new 'Increase Legato'. Then I realised it was the answer for all of those BiaB files you can obtain from other groups on the internet, where the notes were of shorter duration. I used to edit these by using the Piano roll and lengthening each one individually. Now I just use the Increase Legato. It's perfect! Thanks PGMusic!
Above the treble staff, towards the left, look for a couple buttons that look like tictaktoe boards. The third button in this group turns on "staff roll mode." Here each note has 2 blue lines coming from it. The vertical line is velocity, or loudness. The horizontal line is duration. You can change these lines and their associated values by making the blue lines longer and shorter. Use the right mouse button to do this. The right mouse button.
This is a lesser know feature of BiaB, and it is brilliant. Manipulating the horizontal line will give you as fine a degree of control over the legato values of the melody notes as you could ever want.