sum organisation linq sql?

just removing started linq sql atonement newbie question. i'm perplexing imitate following (working) query linq sql (vb.net):

select
    f.title,
    totalarea = sum(c.area)
from firms f
left join concessions c c.firmid = f.firmid
group f.title
order sum(c.area) desc

(a organization concessions; benefaction an area hectares. i wish list firms starting ones have biggest sum area concessions.)

i'm devising something linq sql homogeneous (pseudo-code)

from f organization db.firms _
order f.concessions.sum(area)

... nonetheless that's right. anyone indicate me right direction?