you can use steam a seam lite, heat & bond lite, or wonder under- as an example- visit your lqs- or a joannes- just make sure the fusable you choose is one that is made to be sewn- the permenent-non-sew fusables are very stiff- will gum up your needles- and stay stiff-hard- the sewable fusables wash away- the project stays nice and soft/pliable.
you can do a buttonhole stitch, a small zig-zag- or any decorative stitch around the edges- sometimes even a straight stitch 1/8" inside the appliques even looks nice.
follow the instructions with the fusable you choose- each one has it's own requirements- some need steam- some a dry iron- and the time is important too- some will tell you to press for 8-10 seconds- some only 2 or 3...it is important to follow the instructions for the product you are using for the best results.,
the applique book should have a section at the beginning that goes over all of the supplies needed- and a resource section in the back telling you where to find them- or the brands they recommend. there are also many tutorials on all kinds of different applique techniques.