Museum of Freemasonry - Masonic Library
After the Entered Apprentice has been invested with the appropriate apron, his situation in the lodge is described in Preston’s Craft Lectures as follows:

Q. Entrusted and invested in the manner described what is his proper situation in the Lodge?
A. At the north-east corner of the Lodge or at the right hand of the Master.

Q. Why is he so placed?
A. That he may tread sure and obey the commands of the Master.

Q. Why does he tread sure at the north-east corner rather than at any other part of the Lodge?
A. Because there he treads on the foundation stone of the building.

Q. To what does it allude?
A. To an established custom of laying the foundation stone of all capital buildings at the north-east corner.

Q. In what form does he appear?
A. With his feet formed into a square, body erect and eyes fixed on the master.

And, of the position for the Fellowcraft it states:

Q. What is the proper situation of the newly accepted Fellow-Craft?
A. In the S.E. Corner of the Lodge at the left hand of the Ruler in his proper situation.

Q. Why?
A. To mark a distinction from the preceding Degree and to show he has been regularly accepted a Fellow-Craft in that situation which is usually assigned to the Second Degree of the Order.

Q. In what form?
A. With his feet formed in a square his body erect and his eves fixed on the Ruler. They are the positions in which the Entered Apprentice and the Fellow Craft are placed after being invested with their distinguishing aprons, but in Masonic progress, there is a third position yet to arise. In some Craft Workings the Deacon is instructed to place the Candidate at the centre of the lodge, and by so doing the Candidate will have stood, figuratively speaking, at the three angles of a triangle; a geometrical figure that at one time abounded in symbolical Freemasonry, now prominently displayed, perhaps even reserved, in the Royal Arch.