How to get every part in a model?

You can get all the parts inside a model or really any instance by using the :GetDescendants() function.

It would look something like this

local model = game.Workspace.Model --//If there is a model in workspace

for i, v in pairs(model:GetDescendants()) do
    print(v.Name) --//Will print out the name of every descendant of the model
end

If you wanted to check just for parts/baseparts, you could do this

local model = game.Workspace.Model --//If there is a model in workspace

for i, v in pairs(model:GetDescendants()) do
    if (v:IsA("BasePart")) then
        --//The part we are currently on inside the loop is a part/basepart
    end
end

More info on GetDescendants here.

Thanks, this is my script with yours but it is not working?

z = script.Parent



while true do 
    wait(1)
    if z.Zombie.Health == 0 then
local charChildren = z:GetChildren()
--"char:GetChildren()" is a table containing all children in Character--
for i,v in pairs(charChildren) do
--"for loop" to run through objects in table--
if v:IsA"Part" then
-- "If Then Statement" to check if current Object is a Part--
print(v.Name .. " -- IS A PART")
-- printing "Object is a Part" if Object passes the Check
end
-- closes the "if then statement"
end
-- closes the "for loop"
    end
    end

Use ":GetChildren()" on the model to get a table of all the children in the model and use an "If Then Statement" to check for parts; Example:

local plr = game.Players.LocalPlayer
local char = plr.Character
local charChildren = char:GetChildren()
--"char:GetChildren()" is a table containing all children in Character--
for i,v in pairs(charChildren) do
--"for loop" to run through objects in table--
if v:IsA"Part" then
-- "If Then Statement" to check if current Object is a Part--
print(v.Name .. " -- IS A PART")
-- printing "Object is a Part" if Object passes the Check
end
-- closes the "if then statement"
end
-- closes the "for loop"