Adding Style Sheet and js files in twig

I am a new in using twig view in slim framework
When i try to link some style sheet or js in twig template this error is acuuer
how i can add external css and js files in twig template
** Message: Unknown “asset” function.**

@Ramyhakam those “asset” function aren’t part on twig, they are part of frameworks like symfony fullstack and probably others got a solution for assets. So you ca try to find a existing solution (twig functions) for slim or build them yourself. A few of them based on the following library: