Roofs protect your house from the cold, the heat, and all types of weather. If your roof is damaged you are at risk of losing money on heating and cooling. Even worse, your damaged roof could lead to water damage that ruins other parts of your home like the ceilings and floors. Here are some tips on roof repair if you have damaged shingles.
It is usually easier to replace an entire shingle than it is to repair a broken shingle. A repair probably won't last as long and you'll need to spend even more time fixing it again.
To replace a shingle you first need to remove the old one. On really old houses the glue holding the shingles in place may have weakened after decades of sun exposure. If that is the case you simply need to pull the shingle out. Be sure to hold down the good shingles around it so they stay in place. If there are any nails holding down the shingle you can use a hammer to remove them.
Put a line of glue on the new shingle, and then put it in the empty spot you made when you removed the old shingle.
For more tips, see the linked video..