How to know "how many working time" is still free by ressource ?

Dear all,
I would like to know if is it possible to know "how many working time" is still free by ressource ?
I explain : we have 4 projects. We want to know if we have enough ressources (humain, mainly) to start a new project.
Where I can't find this information ?
Thanks a lot for your help and for the real good open source software
All the best
Christophe Noisette

Thanks, I found the function.
I can't understand something : we have a meeting in January, 9th (duration : 7,5 hours) (cf. attachment 1738)
In the meeting's detailed form, I could read that for LV (but for every body) has 0,99 h of time non planned. But, in the form "Resource availability " I can see the LV has a lot of available time (attachment 1739).
So the datas seem not comptatible, no?

All the best
Christophe

Thanks again.
I don't understand the last sentence : "Real Work allocation for the resource on meeting date and if issue is confirmed, please report.
Could you be more precise?
Christophe