There are 3 parts of the cell theory.
1. All living things are made up of cell- This means that in order for something to be alive, it must either be a cell or made up of many cells.
2. Cells are the smallest units (or most basic building blocks) of life- They are are the most fundamental units of a living organisms structure. They are also the basic units of function. This means that cells carry out all of the processes necessary for an organism to survive.
3. All cells come from preexisting cells through the process of cell division- This means that in order for a new cell to be created, it has to go through cell division with cells that already exist to become a new cell.
Hope this helps :)