If your home or business has a broken window, you want to call for glass repair right away. Those shards that are still left in the frame can fall out at any time and cause injury, and of course your security or the security of your business may be at risk. Even if you don't fear an intruder through the broken glass, you want to protect your building from rain and pests, and keep people away from the broken glass left in the frame. Note a few tips for covering over a broken window while waiting for a repair person.
Remove the shards
It's good to remove the shards of glass still in the window so they don't fall and cause injury. Wear thick gloves and safety goggles and use pliers to do this, even for smaller pieces. Stand back from the window as you do, since those shards pose a hazard still. Pull out the longest shards as they can cause cuts as you're pulling out smaller ones and start with shards on the top of the window frame, since they are at greater risk of falling out.
If you have plywood you can use, it's good to drill this right into the mortar of the brick of your home or business. Be sure you use a masonry bit for your drill as standard bits will not cut through the mortar. Attach it at the top first so the screws help to hold the weight, and add enough screws along the edges to keep it fitting snugly.
If your home is made from aluminum siding, attach the plywood to the window frame itself. For aluminum and lightweight frames, use lighter screws so you don't bend the frame. You also want a thin piece of plywood so it doesn't add extra weight to the frame.
If you only have cardboard to cover the windows, this won't stop intruders but it can stop weather and keep people away from the window. Use duct tape and tape the cardboard to the inside of the window frame. If you use masking tape or any other variety, it's likely to come off in the slightest breeze. If you tape the cardboard outside the window frame and to the building itself, this also means it will catch more wind and be more likely to come off. You can also increase the stiffness of the cardboard by crisscrossing strips of duct tape across its face, on both sides of the cardboard.
That should keep you safe until your glass can be repaired.