How do you load a marksman model 740 pellet gun?

I would search the web for "Air gun Repair" and locate a shop near you that can repair it or see the link below for shops that repair air guns.

There's a double action to the slide - see the link below for a manual:

please state the make and model. It will make it easier to answer your question.

Follow instructions provide with the item. If you don't have them, contact the maker.

It all depends on the model.