You can't it's a pop toy rifle. Not meant to shoot BB's
On the back of the pistol you will find a long lever, slide it to one side and load in your BBs. Under the barrel you will find a thumb loader to load each shot into the firing chamber between each shot.
I suggest you contact Daisy Directly and ask for an owners manual. See the link below.
To load a Daisy Model 99 BB gun, first ensure the gun is pointed in a safe direction and is not cocked. Open the lever to access the BB reservoir, then pour in BBs until it's full, usually around 50 BBs. Close the lever securely, and then pull back the cocking mechanism to prepare the gun for firing. Always remember to follow safety precautions while handling and using the BB gun.
The Daisy BB gun model 1105 uses standard .177 caliber BBs, which are typically 4.5 mm in diameter. These BBs are commonly made of steel and are coated with a layer of copper or zinc for improved performance and reduced friction. Always ensure to use the appropriate BBs for your specific model to maintain safety and functionality.
To load a Daisy 2002 35-shot repeater, first ensure the gun is pointed in a safe direction. Open the loading port and insert a tube of BBs into the magazine well. Then, push the BB follower down to allow the BBs to feed into the magazine. Finally, close the loading port, and you're ready to shoot.
This model was made by Daisy. Its a model 1894 and shoots standard .177 caliber BBs'
See the link below for the owners manual.
To load a Daisy 35-shot repeater (2003 model) CO2, first, ensure the CO2 cartridge is properly installed in the magazine. Next, pull the magazine out of the gun and place BBs in the feeding slots until full, ensuring they're seated correctly. Reinsert the magazine into the gun, and you’re ready to shoot. Always check for proper functioning before firing.
It would help if you stated the model. Sears sold several different BB guns.
Put in the magazine. load the magazine, and shoot.
750 fps. for BBs, 665 fps. for pellets.
See the link below for the owners manual.