At the back of the slide there should be a stainless steel round button (also is a bullet in the chamber indicater) push that in as far as it goes an lift up slowly on the slide release be careful of springs shooting out....there should be videos on YouTube to help you with this.
If you don't have a manual, ask a gunsmith for help
Ask a gunsmith to show you.
Best thing is to have a gunsmith show you.
Best to ask a gunsmith for help
Best to get some assistance from a good gunsmith
Take it to a gunsmith and ask for help
Find a gunsmith and ask for help
Best left to a gunsmith
Best left to a gunsmith
Best left to a gunsmith
Take it to a gunsmith
Take it to a gunsmith