Planner-list singletasking ressources

[Nicolas Fueyo <nicolasfueyo hotmail com>]

Hello,

Running planner from Software centre on Ubuntu 16.04, I need help 
solving 2 problems :

1° multitasking :

I use 1 ressource (me) and the software makes it like I can multitask 
without limit. How can I set it so that 1 ressource is only used in one 
task at a time ?

2° total cost :

I defined a cost for the ressource. I think it is hour rate, but can't 
find the total cost for the project.

Thanks in advance if you can help me and have a good day anyhow.