But I was afraid to save on fundamental things.

So, at first I learned about the type of soil on the site and the approximate level of freezing, which is necessary to decide on the necessary trench height under the foundation. I decided to make the width of the trench 40cm, although they say that 30cm is usually enough. But I was afraid to save on fundamental things. Then he cleared and leveled the site, made markings. I made it with the help of simple wooden home -made pegs and a thick fishing line. I admit, it was not immediately possible to make all the corners even. Only when the neighbor built nearby advised me to measure the diagonal roulette (if they are equal to one another, the corners will also be correctly exhibited), everything worked out. I marked the internal boundaries in the same way, always checking the diagonal after this.