First some definitions: a "tie" bridges two or more notes of the same tonal value to extend its duration across beat or measure lines, or create a note duration not divisible by 2, (1/2+1/8), or note durations longer than a full measure. A "slur" groups a series of notes of different tonal value to be sung with a single lyric word or syllable, or to be played as a smooth transition between them.
You add a tie either in the "Normal" or "Manual" mode by right-clicking on the first of two or more consecutive notes. The note becomes selected, and a drop-down menu appears under the cursor. While keeping the right mouse button depressed, scroll down to "Tie/Untie to Next Note," Then leave up on the mouse button to apply or remove a tie. You may apply ties all at once to a series of notes by shift-clicking all but the last note, then right-clicking to activate the drop-down menu. You can also use the shortcut in the "Normal" mode by selecting all but the last note of a series, then type the shortcut key "t."
To apply a slur, you must right-click on a tie, then select "Convert to Slur" from the drop-down menu. With the slur selected, click on its end and drag it to the end of the note series. While in the "Normal" mode, you may use the short-cut key, "s" to slur the selected note to the next note. You can also select the first note, then "shift-click the last note in a series followed by typing "s" to slur the entire series of notes at once. The slur function does not toggle. You must select the slur, then depress the "delete" key to remove it. Slur direction (same as the note stems) and as well as conditional slur (dotted line slur) can be changed through the slur drop-down menu,
ScoreCloud short-cuts are listed in the User Manuel: http://scorecloud.com/support/manual/
For an example of ties and slurs, check out my song, "The Fabric of Life" https://my.scorecloud.com/song/b99d08146326082d68eb12640ff13fb9