plunging endmill

Hi,

I am very new to machining as well as to CNC and will like to ask the
group about the advisability of plunging an endmill vertically into a
workpiece. I am using the set of 6 endmill purchased from Sherline
(does these have cutting edges on its bottom)

Initially, I plan to cut only softer materials like wood and plastic.
Do I need to program the cutter to enter tangentially, or is it
sufficient to plunge them straight vertically into the workpiece.

Any comments and advice highly appreciated

Heroaku