To start the building you need to have 20M lumber, 10M silver 2k Ale, 2k Plates and 100 "Scrolls". It is not possible to use Gold for upgrade. Building time for level 1 is 1w 3d 0h. Only the Chief or any of the Elders can start a construction process, but all clan members can send rss to the Stronghold Resource Storage.
For speeding up the building process or the woodworking process you use a Stronghold Boost.
For level 1 the stats are
Maximum of TImber recieved: 2000
Stronghold Influence: +62M
(someone else can make a proper table later)