Ah crap, now you gunna get me talking..... *sigh*
Okay...... I'll cover a couple of things.
Kemet (kmt in their language) is "black land", which represents the black soil brought down the Nile by the yearly floods to the Nile Delta (Lower Egypt). We know this to mean the land not people through the use of the hieroglyph 𓊖 which denotes a location. The same hieroglyph is used at the end of city names.
Deshret (dsrt in their language) is "red land", which represents the deserts surrounding the Nile Valley. Deshret came to represent "outside Kemet", or foreign lands, since Kemet was seen as the safe, fertile lands of the Nile, and deshret was seen as the hostile lands outside the safety of the Nile valley. It also means the red crown which is part of the Pschent double crown for Kemet.
Remen Kemet (rmn-kmt) is "people of the black land", which represents the people of Kemet themselves.
The word Pharaoh (
pr-ꜥꜣ in their language) is "great house". This is from the hieroglyphs representing the house (box with opening on the bottom) and great (horizontal wooden column). From the earliest time of Kemet through to the 18th Dynasty, Pharaoh represented the line of Pharaohs. Not a specific Pharaoh, but the line itself (from the column). Hm was used when referring to the person who was King. Sometime in the 18th Dynasty, possibly Thutmose III, but definitely by Akhenaten, Pharaoh's use changed from the line of Pharaohs, to Pharaoh themself as a ruler. It became a title. And by the 23rd Dynasty the use of Hm had all but disappeared.
Next we get to the "two lands" bits. Still with me?
Lower Egypt is regarded as the Nile delta, and some way up river (southwards). Think from around modern Faiyum to the sea. Bjtj means "one with the bee". The bee is the symbol of Lower Egypt. When the bee hieroglyph is combined with a loaf and sitting person with the red deshret crown hieroglyphs, means King of Lower Egypt.
Upper Egypt is regarded as the Nile from where Lower Egypt ends, to the first cataract south of modern day Aswan. Nswt means "of the sedge". The sedge is the symbol of Upper Egypt. Again, when the sedge hieroglyph is used with the loaf and water hieroglyphs, means King of Upper Egypt. The King of Upper Egypt wore the white hedjet crown.
Together, nswt-bjtj is the combined King of Upper and Lower Egypt. The pschent is the combined crown of Upper and Lower Egypt, being the white crown placed inside the red crown. Nswt-bjtj means "of the sedge and the bee", and is the title given to the current King of both lands. In this way, the pschent, nswt-bjtj, and "the sedge and the bee", became known as "the two lands".
Note that "the two lands" does not mean Kemet and Deshret. It means Upper and Lower Egypt.
EDIT: Just to note that "Hm", used when referring to the King, is similar in meaning to the English HM Charles III. Hm in Kemet was pretty much "his/her majesty".