[FMadera]

Ok, I'll go through it (since I saw it a bunch this weekend at my college matches).

You can have either:

Substitution, and then the libero replaces the person subbing in, or;

Replacement for the correct player, followed by the substitution.

For example:

10 is the MB who can't serve, 1 is the server for her, and 6 is your L.

1 subs for 10. Your lineup card would read 10/1, as would the scoresheet line item (10, followed by one, not 10 for 1, just to be clear).

1 is done serving, so you can either have:

10 subbing back for 1, with L replacing 10, then 10 can replace L when she goes back to the front row, which the tracker would show as 10/1/10/L/10, or;

L can replace 1, but when 10 comes back to the front row, then you have to have the libero replacement of L for 1, followed by 1 subbing for 10, which the tracker would show as 10/1/L/1/10..

Either way, your card would look like 10/1/10.