For a page that explains the difference between American English and British English musical terms, click here.

Make sure you have View > Layout Marks checked; you will see a blue dotty blank page symbol above the first bar. Select this and Delete.

Typically on playback, there is an unwanted attack on the second note. You are probably using slurs. Be sure to understand the difference between slurs and ties, they fundamentally have different meanings, although both are drawn as arcs (the tie is actually flatter and is always horizontal).

Ties are used to augment the duration to play a note. A tie joins a single note to only one other at the same pitch and immediately after the first note. To input a tie, select the first note and type Enter on the numeric keypad (not Enter/Return above Shift).

Slurs are used to indicate phrase marks, ligation and articulation. A slur may span two or more notes or chords (and possibly multiple staves as well). To input a slur, either select the first note that the slur spans, type S and then as many spaces as necessary until the slur is the right length, or select a passage and type S.

Just perform a search on the Wiki or look at the index :)