Fusing interfacing to the fabric before cutting out the pattern is known as block fusing. This method will eliminate concerns about shrinkage of pattern pieces from the fusing process and the fusing process is easier when working with a large piece of material. Cover a table with towels and lay the fabric out flat before fusing.
The bonding process for most interfacings is meant to be permanent. Test fuse a piece of fabric before using it on your garment pieces. Make sure that the combination of fabric and interfacing is giving you the result that you want. This is a time to try different types of interfacing and practice fusing techniques.