What will happen if the cloud does not have enough mass?

When the contracting gas and dust from nebula become so dense and hot that nuclear fusion starts ... A protostar is a contractingcloud of gas and dust with enough mass to form a star while a staris made up of large amount of gas and relatively small volume.

The clouds were the fundamental unit in the formation of the solar nebula and were comprised of a significant amount of mass. These clouds have fused with the matter, interstellar dust particles along with gravity because of the force of gravity. Due to this fusion, the solar system started to form.

If the clouds were not of enough mass then they would simply scatter in space randomly. So in the absence of enough cloud mass, there would have not favorable conditions for the solar system to form.