In Yoma 54, it says the world was created with the Even Shesiya (primordial rock).
Is this to be taken literally and if yes, do we have details into this process?
Art Scroll Talmud Yomah 54b1 note 9 explains that the even shesiyay is symbolic of the purpose of the world and the ideal on which it is founded (Meiri). Notes 10, 12, and 25 cite Rashi, that it was created first and the clods of earth were added to it to expand the creation until the entire world (and universe of matter) came into being.
That is, this stone represents the purpose of the world and the ideal for which it was founded (see Meiri). The Shessiyah stone is the foundation of the world because it is the place of avodah in the Temple, and the Mishna teaches (Pirkei Avos 1:2): THe world stands upon three things: upon the Torah; upon the avodah; and upon the perfomance of kindness (Rambam, Commentary to the Mishna here; see also Rabbeinu Yonah to Avos loc. cit; cf. Ramban to Bereishis 1:1 and 1:8 and Peirush Shir Hashirim Hmeyuchas LeRamban 3:9).
The world began with one bedrock and clumps were attached all around it (Rashi).