VBA: Locking rows before filling out all cells

[Mireia173]

Let's see if I make myself clear.

I have a Range (A:J) of cells that my employers have to fill out with data. What I need to do is to lock all rows (A/J) so they can not active cells from the following row to XX before filling out cells of A:J.

For example, to unlock A4 to F4, they first need to complete cells from A3 to F3, if that happens, then row A4 to F4 will be unlocked ready to start filling cells before unlocking A5:F5, and I need this to do the same thing with all my rows (XX)

How could I do this??

Thanks in advance!