exodus 40:2 On the first day of the first month shalt thou set up the tabernacle of the tent of the congregation. - Free Bible Online

      2. On the first day of the first month--From a careful consideration of the incidents recorded to have happened after the exodus (Ex 12:2; 13:4; 19:1; 20:18; 34:28, &c.), it has been computed that the work of the tabernacle was commenced within six months after that emigration; and consequently, that other six months had been occupied in building it. So long a period spent in preparing the materials of a movable pavilion, it would be difficult to understand, were it not for what we are told of the vast dimensions of the tabernacle, as well as the immense variety of curious and elaborate workmanship which its different articles of furniture required.
      the tabernacle--the entire edifice.
      the tent--the covering that surmounted it (Ex 40:19).

JFB.