i just want to transpose my sequence or selected sequences a octave higher or lower. i cant find any easy way to do this.

Right mouseclick in a part than you get functions-> transpose
Probably in steps of 1/2 (chromatic) ..so +12 = 1 octave

Note: you know that one octave on your keyboard has 12 keys ( 5 black and 7 white ones )
To go from the start key of the octave to the new octave above (or below) it takes 12 x 1/2 steps between the keys ( the key distance can be a half or one step between the keys if you use only white keys)
If you go from the start key and use all 12 keys that it are 12 x 1/2 steps
So you can calculate the transposition ..say a major third(interval) ..the distance is 2 steps (from the first white key to the third white key is 1 + 1 keystep
To fill in is +2 in MUlab for major third interval as example

Transposing the sequence is one way, but note this will affect all parts playing this sequence. For more info on unique/shared sequence parts, see http://www.mutools.com/mulab/docs/composer.html "Sequence Parts".

If you quickly want to transpose a single part, select that part (click it) then you have the part property panel at the lower left of the composer where you can change the transpose and velocity of that sequence part