How should I put my car in overdrive? 10 points!?

I have a 1997 ford escort, and i have over drive,drive,L,N and reverse as my options. i was told to use over drive for when i go 45 and up but i was wondering if there is a certain way i should switch should i not press the gas when switching from over drive or to over drive? Im just curious if there is a certain way i should do it?