The triangles designate the type of wall, or other partition, so " 1 " might be concrete blocks, " 2 ' might be the little red bricks ( horror, horror !), etc. If you look at the bathroom, the outer wall is one material, inner is another....probably tiles in this case ?
circles are for the type of door (D1/D2, etc) , hexagons for the type and size window (W1/W2). Included in the plans will be a list of all these detailing sizes, materials, even particular brands.
The boxes F1/C1 designate the type of floor or ceiling finish, so F1 might be ordinary floor tiles, F2 for bathroom tiles, and F3 for outdoor patio tiles. Next to them is the floor and ceiling heights, so the living room is +1.00 (one meter above normal ground level) while the bathroom is lower at 0.90m. Ceilings are 3m, and 2.7 in the bathroom. Well, that's the normal use anyway.
!!!! But I am confused as to why the bedroom floor is shown at 2.80m and the ceiling is at 3m ....either somebody has made a mistake or it is a bedroom for very tiny midgets with only 20cms headroom ! Runker ??