You can select adjacent cells, then merge them into a single cell. Conversely, you can take a large cell that has been created by merging single cells, and divide it back into individual cells.
When you copy cells into a target range containing merged cells, the target range gets unmerged first, then the copied cells are pasted in. If the copied cells are merged cells, they retain their merge state.
Elektu la apudajn ĉelojn.
Choose Format - Merge Cells - Merge Cells. If you choose Format - Merge Cells - Merge and Center Cells, the cell content will be centered in the merged cell.
Metu la kursoron en la dividotan ĉelon.
Choose Format - Merge Cells - Split Cells.