how to use table?

[hyein6790]

local tbl = {["ValveBiped.Bip01_Head1"] = {
x = 0,
y = 0,
z = 100,
}}

PrintTable(tbl)

result
ValveBiped.Bip01_Head1:
x = 0
y = 0
z = 100

how to insert "ValveBiped.Bip01_Neck" with {x = 0,y = 0,z = -100} into the tbl?
but not this way
local tbl = {["ValveBiped.Bip01_Head1"] = {
x = 0,
y = 0,
z = 100,
},
["ValveBiped.Bip01_Neck"] = {
x = 0,
y = 0,
z = -100
}}
this way isn't what i want
i already declared table
just insert ["ValveBiped.Bip01_Neck"] = { x = 0, y = 0, z = -100} into table

[jwgamesuk]

local tbl = {} --declares "tbl" as a table
tbl["ValveBiped.Bip01_Beck"] = {x = 0, y = 0, z = -100} --table variable["key"] = data

[LoweChaser]

tbl["ValveBiped.Bip01_Head1"] = {
x = 0,
y = 0,
z = 100
}

[hyein6790]

thanks for your help