it really should be that simple.
check the installation version - go to help->, then click the "Installation Information" button - look for the version next to "PHP Development Tools (PDT) all-in-one SDK v3.0.0" - also check the "Eclipse SDK" should be 3.7 .0
ensure that the perspective is selected, - next to the perspective buttons - click the icon with the "+" symbol - select "other" - highlight "PHP" - select "OK, now PHP will be included in the list of open perspectives
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