Not that hard of a tasks; assuming no prior accident damage to firewall or rails (so as to not have some reference points to work off of).
I explain some details I encountered in mine, not in any particular assembly order, but as they come to mione.
Shock Tower & Diagonal Braces: Weld-in after inner panels are positioned close to required. Both act to stiffen the inner panels; not so much as to locate them.
Radiator Upper Support: This will serve to determine spacing of inners at front/top corners. I used the oblong holes as references.
Upper Firewall Brackets: If you replaced them wrt to original markings, you should be fine.
Front Rad. Side Panels: Placement fairly simple. Bottom tabs snug into rail corners. Top: align to ref. holes in upper rad. support.
Squaring/Alignment: I used holes on top section of cowl-ls/rs: diagonally to from corners of rad support.
Buy youself a bunch of visegrips +/or c-clamps. As you'll want to temp. secure many parts together & will be repositioning frequently before any welding is started. When you start to weld parts: do only the minimal tack welding possible to secure. If any need to be relocated/moved: much easier to undo welds.
