Where do i precache models

[BJOLER]

Hello so i am currently building up a server for the first time and i am having some issues with enteties that creates huge lagspikes on user end first time they spawn it in

i know that i am supposed to precache the files and i am supposed to use a code that looks like this : "util.PrecacheModel( string modelName )" and i do know i have to change "modelName" to the models id

now the problem is i have no clue where i am supposed to insert that code

all i got is this link [url]https://wiki.garrysmod.com/page/util/PrecacheModel[/url]

if someone could give me some directions that would be wonderfull