Begin by looking over the entire composition. You are looking for the following issues that may present problems arranging for piano: different rhythms between each part and divided parts in which one part plays more than one note.
Address any issues discovered before arranging the music. If there are different rhythms, use the rhythm for the melody (usually the highest voice) and bass part only. If problems with divided parts exist, check to see if it is written in a way that can be divided between both hands. Generally, you want to avoid writing independent lines in a single hand since they are difficult to play.
Write the bass clef and the tenor part in the bass clef of the piano staff. Pay special attention to anything that may present problems such as different rhythms and intervals of more than an octave. Keep the distance between the parts less than an octave. This may require transposing the bass up an octave.
Finish writing the piece by copying the soprano and alto part into the treble clef. If it makes it easier to play, you can copy the tenor into the treble clef as well. It depends on whether the tenor is moving at rhythmically the same speed as the alto. Don't be afraid to change the octave of a part to make it easier to play.