Screen roller, a tool you will quickly wish you had once you need to fix a slider door using a screwdriver blade to push in the cloth.
The screwdriver method does work as well a the old blunt chisel, its just tough on the hands.
I use a roller like the one in the link below and what I like about it is that its very useful for narrow frames and very small spline sizes.
The other size roller I use is much heavier and has a wide flange which helps shape aluminum cloth properly into the the frame while you are rolling.
There are a number of different types of professional rollers, some with narrow wheels for pushing in small diameter splines, and others with thick wheels for thicker splining.
Some also have built in cutters for trimming the cloth while others have different diameter rollers on each end.
The spline roller in the link below is one without a bearing but is a decent compromise if you are a do it yourselfer and want to fix your own screens.
The screening roller pictured below is used for spline sizes .130 to .180 which covers you for the most common sizes. It would also work with .250 spline. It would just be a little slower than a larger heavier roller.
You can get screening installation tools in most hardware stores. The most common is the kind that has a steel washer for a roller riveted into a plastic handle. These will work all right but are no good if you have a lot of screens to fix as they will quickly break.
An old blunt chisel or flat blade screwdriver is also necessary to help guide the spline around the corners of the frame. Much easier than doing this all around the frame
Avoid the installation tools that look like plastic knives with a thick blade. They are easily available in just about any good hardware store but they are just too awkward to use.
You will just wind up with blistered hands from doing one patio door. As well you will have to push so hard that its likely the cloth will end up getting damaged.