The Tie
In music notation, a tie is a curved line connecting the heads of two notes, in the case of the chord chart below it’s connecting a chord. In the following example the + of beat 2 is tied to beat 3 – that’s two 1/8th notes tied together which equals a 1/4 note.
In terms of strumming, play the + of beat 2 as you normally would and simply skip the down strum on beat 3, wait, let the chord ring, then play the up strum on the + of beat 3.
Having two up strums side by side may take some getting used to and you may find it hard to tap your foot on beat 3 as that’s where the strum was, but hold your ground and keep the regular count happening with your foot.